study instruments in research

Research Methodologies: Research Instruments

• Research Methodology Basics
• Research Instruments
• Types of Research Methodologies

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Types of Research Instruments

A research instrument is a tool you will use to help you collect, measure and analyze the data you use as part of your research.  The choice of research instrument will usually be yours to make as the researcher and will be whichever best suits your methodology. 

There are many different research instruments you can use in collecting data for your research:

• Interviews  (either as a group or one-on-one). You can carry out interviews in many different ways. For example, your interview can be structured, semi-structured, or unstructured. The difference between them is how formal the set of questions is that is asked of the interviewee. In a group interview, you may choose to ask the interviewees to give you their opinions or perceptions on certain topics.
• Surveys  (online or in-person). In survey research, you are posing questions in which you ask for a response from the person taking the survey. You may wish to have either free-answer questions such as essay style questions, or you may wish to use closed questions such as multiple choice. You may even wish to make the survey a mixture of both.
• Focus Groups.  Similar to the group interview above, you may wish to ask a focus group to discuss a particular topic or opinion while you make a note of the answers given.
• Observations.  This is a good research instrument to use if you are looking into human behaviors. Different ways of researching this include studying the spontaneous behavior of participants in their everyday life, or something more structured. A structured observation is research conducted at a set time and place where researchers observe behavior as planned and agreed upon with participants.

These are the most common ways of carrying out research, but it is really dependent on your needs as a researcher and what approach you think is best to take. It is also possible to combine a number of research instruments if this is necessary and appropriate in answering your research problem.

Data Collection

How to Collect Data for Your Research   This article covers different ways of collecting data in preparation for writing a thesis.

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What is a Research Instrument?

• By DiscoverPhDs
• October 9, 2020

The term research instrument refers to any tool that you may use to collect or obtain data, measure data and analyse data that is relevant to the subject of your research.

Research instruments are often used in the fields of social sciences and health sciences. These tools can also be found within education that relates to patients, staff, teachers and students.

The format of a research instrument may consist of questionnaires, surveys, interviews, checklists or simple tests. The choice of which specific research instrument tool to use will be decided on the by the researcher. It will also be strongly related to the actual methods that will be used in the specific study.

What Makes a Good Research Instrument?

A good research instrument is one that has been validated and has proven reliability. It should be one that can collect data in a way that’s appropriate to the research question being asked.

The research instrument must be able to assist in answering the research aims , objectives and research questions, as well as prove or disprove the hypothesis of the study.

It should not have any bias in the way that data is collect and it should be clear as to how the research instrument should be used appropriately.

What are the Different Types of Interview Research Instruments?

The general format of an interview is where the interviewer asks the interviewee to answer a set of questions which are normally asked and answered verbally. There are several different types of interview research instruments that may exist.

• A structural interview may be used in which there are a specific number of questions that are formally asked of the interviewee and their responses recorded using a systematic and standard methodology.
• An unstructured interview on the other hand may still be based on the same general theme of questions but here the person asking the questions (the interviewer) may change the order the questions are asked in and the specific way in which they’re asked.
• A focus interview is one in which the interviewer will adapt their line or content of questioning based on the responses from the interviewee.
• A focus group interview is one in which a group of volunteers or interviewees are asked questions to understand their opinion or thoughts on a specific subject.
• A non-directive interview is one in which there are no specific questions agreed upon but instead the format is open-ended and more reactionary in the discussion between interviewer and interviewee.

What are the Different Types of Observation Research Instruments?

An observation research instrument is one in which a researcher makes observations and records of the behaviour of individuals. There are several different types.

Structured observations occur when the study is performed at a predetermined location and time, in which the volunteers or study participants are observed used standardised methods.

Naturalistic observations are focused on volunteers or participants being in more natural environments in which their reactions and behaviour are also more natural or spontaneous.

A participant observation occurs when the person conducting the research actively becomes part of the group of volunteers or participants that he or she is researching.

Final Comments

The types of research instruments will depend on the format of the research study being performed: qualitative, quantitative or a mixed methodology. You may for example utilise questionnaires when a study is more qualitative or use a scoring scale in more quantitative studies.

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Clara is in the first year of her PhD at the University of Castilla-La Mancha in Spain. Her research is based around understanding the reactivity of peroxynitrite with organic compounds such as commonly used drugs, food preservatives, or components of atmospheric aerosols.

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Research Instruments

• Resources for Identifying Instruments
• Assessing Instruments
• Obtaining the Full Instrument
• Getting Help

What are Research Instruments?

A research instrument is a tool used to collect, measure, and analyze data related to  your subject.

Research instruments can  be tests , surveys , scales ,  questionnaires , or even checklists .

To assure the strength of your study, it is important to use previously validated instruments!

Getting Started

Already know the full name of the instrument you're looking for? 

• Start here!

Finding a research instrument can be very time-consuming!

This process involves three concrete steps:

It is common that sources will not provide the full instrument, but they will provide a citation with the publisher. In some cases, you may have to contact the publisher to obtain the full text.

Research Tip :  Talk to your departmental faculty. Many of them have expertise in working with research instruments and can help you with this process.

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Advanced Research Instrumentation and Facilities (2006)

Chapter: 2 introduction to instrumentation, 2 introduction to instrumentation.

T his chapter introduces the subject of instrumentation in general; defines the particular instrumentation that is the subject of this report, advanced research instrumentation and facilities (ARIF); and gives examples of ARIF used in various fields.

WHAT IS INSTRUMENTATION, AND WHY IS IT IMPORTANT?

Instruments have revolutionized how we look at the world and refined and extended the range of our senses. From the beginnings of the development of the modern scientific method, its emphasis on testable hypotheses required the ability to make quantitative and ever more accurate measurements—for example, of temperature with the thermometer (1593), of cellular structure with the microscope (1595), of the universe with the telescope (1609), and of time itself (to discern longitude at sea) with the marine chronometer (1759). Instruments have been an integral part of our nation’s growth since explorers first set out to map the continent. The establishment of the US Geological Survey had its roots in the exploration of the western United States, and its activities depended critically on advanced surveying instruments.

A large fraction of the differences between 19th century, 20th century, and 21st century science stems directly from the instruments available to explore the world. The scope of research that instrumentation enables has expanded considerably, now encompassing not only the natural (physical and biologic) world but

also many facets of human society and behavior. Instrumentation has often been cited as the pacing factor of research; the productivity of researchers is only as great as the tools they have available to observe, measure, and make sense of nature. As one of the committee’s survey respondents commented,

without continued infrastructure support…. We will see many young investigators changing the nature of the projects and science they do to areas that have less impact but assure better chances of success. The lack of instruments or the ability to upgrade aging local facilities simply dictates the science done in the future. 1

Cutting-edge instruments not only enable new discoveries but help to make the production of knowledge more efficient. Many newly developed instruments are important because they enable us to explore phenomena with more precision and speed. The development of instruments maintains a symbiotic relationship with science as a whole; advanced tools enable scientists to answer increasingly complex questions, and new findings in turn enable the development of more powerful, and sometimes novel, instruments.

Instrumentation facilitates interdisciplinary research. Many of the spectacular scientific, engineering, and medical achievements of the last century followed the same simple paradigm of migration from basic to applied science. For example, as the study of basic atomic and molecular physics matured, the instruments developed for those activities were adopted by chemists and applied physicists. That in turn enabled applications in biological, clinical, and environmental science, driven both by universities and by innovative companies. A number of modern tools that are now essential for medical diagnostics, such as magnetic resonance imaging scanners, were originally developed by physicists and chemists for the advancement of basic research.

WHAT IS “ADVANCED RESEARCH INSTRUMENTATION AND FACILITIES”?

Borrowing from the terminology used by Congress in its request, the committee’s study focuses on the issues surrounding a particular category of instruments and collections of instruments, referred to as advanced research instrumentation and facilities. In the charge to the committee, ARIF is defined as instrumentation with capital costs between $2 million and several tens of millions of dollars. In that range, there is no general instrumentation program at either the

National Science Foundation (NSF) or the National Institutes of Health (NIH), yet they are the primary federal agencies that support instrumentation for research outside the national laboratories. The instruments and facilities in this price range fall under neither NSF’s Major Research Instrumentation program nor its Major Research Equipment and Facilities Construction account. The committee found that there are no general ARIF programs at the other federal funding agencies.

The committee identifies other characteristics of ARIF that should be part of its definition. Many qualities distinguish ARIF from more easily acquired instrumentation. The capital cost of ARIF is not its distinguishing factor, and thus many of the characteristics of and challenges associated with ARIF may apply to instruments and facilities costing less than $2 million. ARIF are

Difficult for individual investigators to obtain and more commonly acquired by large-scale centers or research programs; it is often necessary to have the consensus of a field when attempting to find support for such an instrument or collection of instruments.

Often in need of a substantial institutional commitment for its acquisition, including the availability of proper space and continued upkeep. Multiple federal and nonfederal sources are needed to meet the initial acquisition cost, but the costs of operation and maintenance often require a substantial and long-term financial commitment from the host institution. Many academic institutions—even major research universities—have no ARIF, and institutions that do have ARIF generally have no more than a handful of such instruments or facilities.

Often dependent on PhD-level technical research support staff to ensure that researchers are able to take full advantage of the unique capabilities of the instrument and to keep them in proper operating condition.

Dependent on relatively high-level decision-making. The investment process for ARIF is likely to include the head of a directorate of NSF, a division or directorate external advisory committee, and the vice-president or vice-provost of research at a university. Identifying or renovating appropriate space for an instrument may require the approval of a university provost or president.

Managed by institutions, not individual investigators, because their administration requires a large financial commitment.

Often funded in ways that cannot be easily tracked. Acquiring instruments and facilities often requires multiple sources of funding to meet the initial capital cost. As a result, it is difficult to obtain an accurate picture of contributions of institutions, states, federal agencies, and other supporters.

ARIF includes both commercially available instruments and specially designed and developed instruments and both physical and nonphysical tools. Specially developed instruments are assembled from many less expensive components to make a new, more advanced and powerful instrument. ARIF may be single standalone instruments, networks, computational modeling applications, computer databases, systems of sensors, suites of instruments, and facilities that house ensembles of interrelated instruments. A number of different funding mechanisms support the wide diversity of ARIF.

ARIF can be loosely categorized in two distinct types of use. Some are “workhorse” instruments, essential to everyday research and training. Others are “racehorse” instruments, newly developed or constantly developing, that are perched on the cutting edge of research. Racehorse instruments, because they are novel, are often easier to justify to potential funders. Both workhorse and racehorse instruments are vital for research, and finding the right balance between the two is a challenge.

The “facilities” portion of “ARIF” was incorporated by the committee to emphasize that some research fields and problems require collections of advanced research instrumentation. As has been described earlier, the changing face of research has demanded that a wide array of instruments be brought to bear on a single problem. Collections of instruments are often essential for meaningful research to occur. To solve some types of scientific problems or to engineer new materials, multiple instruments are necessary to carry out a series of steps or processes. Complementary instruments are more effective when housed side by side and may be far more productive than each one is individually.

Historically, centralized facilities have played a large role in research involving

ARIF instrumentation by consolidating resources, increasing collaboration, and making available rare or unique resources to a large number of users. Most publicly funded centralized facilities are located at universities and national laboratories. The state of US research facilities is often cited as an indicator of the nation’s long-term international competitiveness in research. For example, a 2000 National Academies Committee on Science, Engineering, and Public Policy study of materials facilities noted that “rapid advances in design and capabilities of instrumentation can create obsolescence in 5–8 years.” The study further noted that the overall quality of characterization services provided by materials facilities supporting universities and industry had “lost substantial ground” to Japan and Europe. 2 The committee distinguishes between facilities and centers . A center is defined as a collection of investigators with a particular research focus. A facility is defined as a collection of equipment, instrumentation, technical support personnel, and physical resources that enables investigators to perform research.

In referring to ARIF, the committee excludes facilities that house large assemblies of unrelated or only loosely related equipment and that generally require no targeted support staff. Different research fields require different types of ARIF, and some fields have a larger demand for ARIF than others. ARIF are not distinguished by the diversity of research fields or geographic regions it supports.

EXAMPLES OF ARIF

The research community recognizes the importance of instruments. The National Science Board (NSB) recently identified eight Nobel prizes in physics that were awarded for the development of new or enhanced instrumentation technologies, including electron and scanning tunneling microscopes, laser and neutron spectroscopy, particle detectors, and the integrated circuit. 3 Nobel prizes for the development of instrumentation have been awarded in chemistry and medicine for instrumentation related to nuclear magnetic resonance (NMR) or magnetic resonance imaging, and many were also awarded at least in part for the development of ARIF. Many of the ground-breaking instruments that qualified for a Nobel prize or contributed to Nobel prize-winning work began as ARIF and through development have become widely available and more affordable.

Table 2-1 lists the types of ARIF reported to the committee in its survey of institutions. The results of this survey are known to be incomplete and not repre-

TABLE 2-1 Examples of ARIF, by Field

sentative of the state of ARIF on university campuses. Notably absent from this table, for example, are cybertools other than supercomputers, which cost much to develop but little to use. Computer modeling programs are used often by the chemistry and biology community. The cost of acquiring these computational modeling programs is often negligibly small, but the cost of creating them is often substantial. The computational chemistry program, NWChem, for example, cost around $10 million to create and is distributed free. Further details about the committee’s survey and the ARIF reported in it can be found in Appendix C . Table 2-1 is followed by descriptions of several types of ARIF.

Imaging Technologies: From Physics to Biology

Imaging technologies provide many of the best-known examples of the evolution of modern instrumentation. Fifty years ago, studies of the effects of magnetic fields on the nuclear spin states of molecules were at the forefront of esoteric physics research. The earliest magnetic resonance spectrometers were inexpensive to build (they could literally be cobbled together by graduate students from spare radar parts); this was fortunate because measuring nuclear spin properties had no conceivable application. If sensitivity and instrument performance had stayed the same, NMR still would have no conceivable application.

Instead, today magnetic resonance is a fundamental technique for biological imaging and the most important spectroscopic method for chemists, the only one that measures the structure of proteins in their natural environment (in solution). Since 1980, the sensitivity of the best commercially available NMR spectrometers

FIGURE 2-1 Historical capability of NMR spectrometers.

Source: Razvan Teodorescu, “Bruker Biospin Magnets.” Presentation to the National Research Council Committee on High Magnetic Field Science, December 8, 2003.

has improved by a factor of 30. With that advance alone, NMR spectra could be acquired 900 times faster today than 25 years ago. Improvements in resolution and pulse sequences make the advances in NMR spectrometry even more dramatic. Figure 2-1 shows how NMR resolution and sensitivity have progressed since 1980.

Modern, very-high-field NMR spectrometers (high fields help to resolve the many atoms found in large molecules) are complex instruments; the most advanced machines today cost millions of dollars. The next generation, which pushes to still higher magnetic field strengths, will require a concerted effort in superconductor physics and radiofrequency design but will create even further dramatic extensions of the applicability of the technique. 4

The pioneers of magnetic resonance would never have dreamed that 50 years later the International Society of Magnetic Resonance in Medicine would have 2,800 papers and 4,500 attendees at its annual meetings. Today, magnetic resonance imaging is a mainstream diagnostic tool, and functional magnetic resonance

imaging (literally, watching people think) promises to revolutionize neuroscience and neurology. Again, the applications and the expense are intimately coupled to the sophistication of the technology: a modern, commercially available 4 Tesla whole-body magnetic resonance imager can easily cost $10 million to acquire and site, and it requires highly specialized technical staffing to maintain its perfor-

mance. For the institutions that responded to the committee’s survey, the annual cost of operation for magnetic resonance imagers averaged 10% of the capital cost.

Modern methods in optical and x-ray imaging also reflect the evolution from physics to more applied science. They are not simply descendants of van Leeuwenhoek’s crude microscope and Röntgen’s x-ray hand picture; they embody

and enhance our understanding of molecular and cellular structure and function. It is only a slight exaggeration to say that the most important application of the crude lasers of the 1960s was as inspiration for science-fiction television and movie weapons. Today, advanced laser systems permit microscopy hundreds of times deeper into tissue than would be possible with an ordinary microscope, and they are central to the rapidly growing field of molecular imaging.

The National Cancer Institute has identified molecular imaging as an “extraordinary opportunity” with high scientific priority for cancer research. The most promising approach is the development of new technologies and methods to improve the imaging and molecular-level characterization of biologic systems.

In the committee’s surveys of researchers and institutions, NMR spectrometers were among the most commonly cited individual instruments, and advanced models were among the most commonly sought. The availability of ARIF in general was of concern to many researchers for whom access to increasingly advanced instruments was the key to advancing science and providing solutions to societal problems. The NMR spectrometer, as it becomes more and more sophisticated, exemplifies the issue. As one researcher noted,

there is an increasing need for advanced research instrumentation in many fields. Many instruments that start out appearing to be expensive and esoteric rapidly become mainstream. The good side of this is that these instruments fuel impressive scientific results. The bad side is that scientists who do not have access to these instruments tend to fall behind in terms of their results and in what experiments they can propose in grant applications.

… Five or six years ago, few labs had access to very high field spectrometers (750 MHz or above), but now the field has been pushed ahead to where many … projects require such instrumentation. A significant number of researchers have access to these machines, but many either don’t have access or must drive/fly long distances to obtain access. While on paper it sounds fine to ask a researcher to travel to a high field spectrometer, in practice this is very cumbersome and does not lead to cutting edge results. For any particular NMR project, a dozen or more different NMR experiments must be carried out on a sample…. Traveling back and forth to a “richer” or better endowed university is not conducive to getting results. 5

High-Speed Sequencers and the Human Genome Project

One of the major accomplishments of science in the 20th century was the deciphering of the human genome. That achievement made it possible to understand the molecular basis of human life in unprecedented detail. The potential for

improving health and curing disease has already been demonstrated, but most of the benefits remain to be seen. The achievement will provide the basis of discoveries far into the future.

The genetic information in DNA is stored as a sequence of bases, and DNA sequencing is the determination of the exact order of the base pairs in a segment of DNA. Two groups, in the United States and the United Kingdom, first accomplished sequencing in 1977 and were awarded the 1980 Nobel prize in chemistry. However, their approaches were time-consuming and labor-intensive. Further

advances came in 1986-1987 with the development of fluorescence-based detection of the bases. That led quickly to automated high-throughput DNA sequencers that were soon commercialized and made generally available to the research community. However, the speed of those devices was still not sufficient to decode the human genome in any reasonable amount of time.

Beginning in 1990, the pressures of approaching the daunting task of sequencing the human genome produced a number of new advances, which resulted in a fully automated high-throughput parallel-processing device that was 10 times faster than the older method. The progress and success of the Human Genome Project constitute a case study in instrumentation and of how, without develop-

ment, it can become a pacing factor for research. The leaders of the sequencing efforts at the Department of Energy Office of Science and NIH recognized that the existing technology was not capable of sequencing fast and cost-effectively. As a result, they invested substantially not only in researchers but in the further development of sequencing technologies. The tandem approach proved very successful.

Genome sequencing requires the assembly of millions of fragments into a complete sequence. By itself, the mechanical process of sequencing was not sufficient to map the human genome in a reasonable time. The project was aided by computer algorithms developed by researchers in the late eighties and early nineties. The confluence of hardware and software development made it possible to complete the human genome sequence years before it had been considered possible. It also provided a general approach to large-scale sequencing that has resulted in the understanding of the genomes of a wide variety of organisms. The knowledge of genomes of a number of organisms has vastly accelerated discovery in basic biology research.

The history of the genome project shows how technology development can influence the course of discovery. Hardware and software were both needed and

were synergistic. The parallel development of sequencers and software demonstrates that not only key insights but also incremental improvements can make a qualitative difference in the progress of science.

Today, computers are vital tools to scientists and engineers. Indispensable for communication and often used in conjunction with many instruments, the computer can also be a scientific instrument itself. This section gives examples of three types of cybertools that are fundamental to several fields of research: software, data collections, and surveys.

Although one of the first scientific applications of digital computers in the 1940s was to try to predict the weather—with grants from the US Weather Service, the Navy, and the Air Force to John von Neumann at the Institute for Advanced Study at Princeton University—scientific applications software aimed at obtaining

a better understanding of physical phenomena did not become widely available until the 1960s and 1970s. Scientists and engineers have since developed a broad array of scientific software applications that are acknowledged to be indispensable in the scientist’s toolkit—the software equivalents of the NMR spectrometer and other instruments described above. Examples of such applications software in use today are Gaussian, a molecular modeling code that is used by experimental and theoretical chemists to understand molecular structure and processes better and more easily by performing computer “experiments” rather than chemistry experiments; the Community Climate System Model, which is used by the climate research community to understand the evolution of past and future climates; and CHARMM and AMBER, used by the biomolecular community to understand the structure and dynamics of proteins and enzymes.

Scientific applications, such as Gaussian, often began as small research projects in the laboratory of a single investigator. However, as the capabilities of computers increased, the applications included models of the physical and chemical processes of higher and higher fidelity, and the software became more and more complex. Today, many of the scientific applications involve hundreds of thousands to millions of lines of code, took hundreds of person-years to design and build, and require substantial continuing support to maintain, port to new computers, and continue to evolve the capabilities of the software as new knowledge accumulates. The cost of developing major new scientific and engineering applications can be more than $10 million, and the cost of continuing maintenance, support, and evolution exceeds $2 million per year. Thus, these software applications are well within the category of advanced research instrumentation being considered in this report.

Digital data collections also provide a fundamentally new approach to research. By gathering data generated in studies on related topics, digital data collections themselves become a new source of knowledge. One of the best examples of a large scientific database that is integral to progress in science and engineering is GenBank, the genetic sequence database maintained for the biomedical research community by NIH. GenBank was born at Los Alamos National Laboratory in 1982, well before the beginning of the Human Genome Project. When the Human Genome Project came into being and the number of available sequences exploded, GenBank became an indispensable repository for the data being generated. Today GenBank contains over 49 billion nucleotide bases in over 45 million sequence records, and the amount of data is increasing exponentially with a doubling time

of less than two years. All sequencing data produced by the Human Genome Project must be deposited in GenBank before it can be published in the literature. Because of the unique role now being played by digital data collections in research and education, the NSB recently drafted a report on the subject, finding that such collections are used in most fields of science, from astronomy (as in the Sloan Digital Sky Survey) to biology (as in The Arabidopsis Information Resource). 6 It concluded that “digital data collections serve as an instrument for performing analysis with an accuracy that was not possible previously or, by combining information in new ways, from a perspective that was previously inaccessible.” The collections are often fundamental tools of the social sciences, housing extensive survey and census results and archived media.

Especially in the social sciences, the survey itself is a scientific instrument that can cost millions of dollars a year to maintain. Longitudinal surveys, large and often decades-long surveys, are analogs to the telescopes and microscopes of the other sciences. These surveys are not created by single investigators; they are often sources of basic data used by arrays of disciplines. Increasingly, surveys collect not only social data but also biomedical data (e.g., cheek swabs for DNA analysis) or are integrated with satellite down feeds or inputs from air quality sensors. The data from these surveys is expensive to collect and document as well as make publicly accessible to researchers while preserving anonymity and confidentiality. They are very expensive to collect in any given round let alone over time. They are also expensive to document and make accessible as public use files, preserving anonymity and confidentiality. Frequently, the data for such surveys can only be collected by one or two survey research centers in the country, such as the Institute for Social Research at the University of Michigan, that possess the ongoing human and local infrastructure to manage them at affordable scale.

Computational technology has advanced to the point where computers can be used as tools not only for remotely accessing databases and collaborating with other researchers but for remotely accessing and controlling scientific instruments. A 900-MHz virtual NMR facility at the Pacific Northwest National Laboratory, for example, supports a national community of users, roughly half of whom use the instrument remotely. The technology can improve and provide less expensive access to instruments for geographically remote users and can permit more effective use of instruments. The openness of this technology and the ability to book at all hours may be a means to generate more revenue from user fees and thus recoup the facility’s operation and maintenance expeditures.

Distributed Advanced Research Instrumentation Systems

Not all advanced research instrumentation is housed in laboratories. Progress in the physics underlying the technological development of modern scientific instruments and their associated cybertools has given rise to an unprecedented explosion in the scope of basic research in the geosciences and biosciences that relies on field observations. Atmospheric scientists, oceanographers, geophysicists, and ecologists are now tackling and solving fundamental problems that require analysis of large numbers of observations that are both time- and space-dependent. Some of the sensors and tools required to make the necessary measurements can be deployed on familiar mobile instrumental platforms, such as oceanographic ships, research aircraft, and earth-orbiting satellites; but many need to be distributed in sensor networks of local, regional, or even global scale. Both physical and wireless networks can be used to transmit data to off-site storage facilities.

A good example of a distributed sensor network is the Global Seismographic Network (GSN), which consists of 130 seismic stations distributed on continental landmasses, oceanic islands, and the ocean bottom. GSN recording and nearly real-time distribution of seismic-wave parameters measurements at numerous sites over the globe serve the needs of basic research in geophysics (such as seismic tomography of the earth’s interior structure) and of applied geosciences (such as earthquake and tsunami monitoring and seismic monitoring of nuclear testing).

Seismometers were originally developed to study earthquakes, but their modern versions, deployed in geographically distributed networks, record data that can be processed with sophisticated computing methods to produce images of the solid earth. The resulting “seismic imaging” is science’s most important source of knowledge about the structure of the earth’s interior and its consequences for humanity with respect to, for example, mineral and energy resources, earthquakes and volcanic hazards.

Today’s seismograph system takes advantage of modern off-the-shelf hardware for many of its components. Global positioning system (GPS) receivers provide the accurate timing required, off-the-shelf electronic amplifiers generate little noise or distortion, and commercial analog-to-digital converters with true 24-bit or higher resolution are an improvement over custom-designed “gain-ranging” systems; but the primary sensor of a modern seismometer still requires unique design to meet a combination of stringent requirements. To detect the smallest signals above the earth’s background “hum,” the self-excitation of the pendulum sensor by Brownian noise must be less than that caused by shaking the instrument’s foundation with an acceleration of 1 nm/s 2 across a wide frequency band of 10 −4 -100 Hz. Furthermore, to make faithful records of the largest earthquakes, the response across the same frequency band must be linear up to excitation amplitudes that are 10 12 times greater than the smallest detectable signals. No company in the United States produces sensors with those capabilities, and no US universities train engineers in seismometer design.

Environmental sensor systems must often be installed in remote field locations, and this poses difficulties not encountered in housing instruments in a laboratory setting. For example, seismometers must be installed in ways that isolate them from drafts, temperature changes, and ambient noise and that protect them from damage by animals and vandalism. Low-power, rugged, and high-capacity data-storage systems are required for remote locations where energy must be provided by fuel cells or batteries recharged by solar or wind-based systems. In locations where Internet service is not available, transmission of data must take advantage of satellites or other telemetry technologies that can substantially add to costs. Although data transmission and interrogation of routine instrument functions can be dealt with remotely, periodic maintenance by technicians is needed

and can account for a large fraction of operation and maintenance costs, especially for large networks with worldwide distribution of stations. Although the combined equipment, installation, and a year of operation and maintenance of an individual station typically will cost between $100,000 and several hundred thousand dollars depending on instrumentation specifications and location (polar regions and ocean-bottom locations are obvious examples of expensive locations), it is clear to the committee that distributed network “instruments” fall well within its definition of ARIF.

Tools for Integrated Circuits

An advanced research instrument may consist of a suite of tools that must be combined to advance a particular field of science and technology and eventually affect society. An excellent example is the microelectronic processing technology

that has been developed over the last 50 years to create integrated circuits (ICs). ICs are found in every electronic product purchased by Americans to enhance our day-to-day living. Communication, education, transportation, defense, health care, and recreation, to name a few examples, have been dramatically transformed by the creation of ICs. In 1947, the first point-contact transistor was demonstrated; it consisted of a sizable chunk of germanium with two gold wires to conduct electricity and enable the demonstration of power gain. A few years later, in 1956, Bardeen, Brattain, and Shockley were awarded the Nobel prize in physics for the discovery of the transistor. Throughout the 1950s and 1960s key technological breakthroughs in crystal growth, ion implantation, photolithography, and planar processing paved the way for the creation of the IC. By fabricating the transistor in a planar form, engineers and scientists could envision methods to interconnect the transistors and begin combining them to perform an unlimited number of functions.

In 1971, Intel introduced its 4004 processor that contained 2,300 integrated and interconnected transistors in a 4 × 5 mm area—about 10,000 transistors/cm 2 . In 1997, the Intel Pentium II processor contained 7.5 million transistors in an area of about 8 × 8 mm. The Pentium III has 28 million transistors; by 2006, the industry projects a logic transistor density of 40-80 million per square centimeter! In 2000, Kilby was awarded the Nobel prize for the invention of the IC. Today, the microelectronic processing technology industry has sales of over $150 billion per year. To create such amazing ultra-high-density, small-area ICs requires a suite of planar processing tools, each of which can be categorized as an advanced research instrument but all of which are needed to build the IC.

As the capability of an instrument increases, its price also increases. For example, in 1982, a physical vapor-deposition tool cost about $400,000; whereas in 2002 a physical vapor-deposition tool cost $7 million. This rise in cost reflects substantial gains in the precision and repeatability of vapor deposition. Similar increases in equipment costs have occurred for other tools in the suite as resolution has increased, feature size has been reduced, and overlay accuracy has been improved. The incredible gains demonstrated by the microelectronic processing technology industry were facilitated by placing the suite of tools within specially designed space or clean rooms to ensure defect-free high-density ICs; such special space adds further to the cost of ownership of these advanced research instruments.

Nanotechnology

Nanotechnology is a broad field that has stemmed from our recently developed ability to manipulate atomic and molecular objects with dimensions 1-100 nm—a length scale that has become increasingly important in pushing the boundaries of operation and performance. It involves the ability to engineer materials on a

nanometer scale by placing atoms into predetermined locations. In light of the broad goals and possible applications of nanotechnology, a large array of synergistic tools has been developed.

A primary need in nanotechnology is the ability to “see” the locations of specific atoms. That has been accomplished largely through the development of scanning probe microscopes. These types of microscopes have the ability to scan or map a surface line by line at atomic resolution. Scanning probe microscopes are distinct from most other microscopes in using mechanical devices, instead of light and lenses, to image surfaces.

The development of scanning probe technology began in 1981 with the scanning tunneling microscope in Zurich. Scanning tunneling microscopes use quantum principles not only to visualize surfaces but also to manipulate them by, for example, initiating chemical reactions. In 1986, the Nobel prize in physics was awarded to the discoverers of this microscopy technique; the remarkably short

time after the initial discovery indicates its importance. Since then, an array of other scanning microcopies have been developed, most notably the atomic-force microscope in 1986 that measured attractive or repulsive forces between a very fine tip and a sample. That approach allowed the imaging of nonconductive surfaces, which the tunneling technique could not do. As is often the case, sophisticated software is required to make sense of the information generated by these tools and to integrate it into a comprehensible image.

The effects of nanotechnology are beginning to be felt, for example, in materials science (nanotubes and nanoparticles), in the development of smaller computer chips, and in the manipulation of biologic components to create nanomotors. Recently, there has been interest in the interaction of “hard” and “soft” materials, which require special facilities where semiconductor fabrication and biomolecular assembly can take place in concert.

Tools for Space Exploration

The exploration of space and the solar system depends on a number of ground-based and space instruments, such as the Supernova Acceleration Probe, a satellite observatory that probes the history of the expansion of the universe over the last 10 billion years. The exploration of space has also become increasingly dependent on diagnostic equipment, whose focus is characterization of samples that have been returned to the earth from space. Such instruments as the MegaSIMS combination spectrometer (see Table 2-1 ), which was specially designed to analyze GENESIS NASA solar wind samples, are ARIF that bridge space and earth exploration and enable us to understand better the materials that make up the world around us and the processes that govern its development.

F2-1: Instrumentation is a major pacing factor for research; the productivity of researchers is only as great as the tools they have available to observe, measure, and make sense of nature. Workhorse instruments, once cutting-edge, now enable scientists to perform routine experiments and procedures much faster. Those tools now have efficiency and sensitivity greater by several orders of magnitude than a decade ago. Research that previously took years to conduct now takes hours. Most of the research funded by the federal government today would be impossible with tools that were developed in decades past.

F2-2: As new research questions are answered, more advanced instrumentation needs to be developed to respond to researcher needs. As a result, the useful life of instruments has shortened dramatically in recent decades, and the demand for new instruments has increased. Instruments that used to be relevant to cutting-edge research for a decade or more today last less than half that time. Older instruments are still useful, but the demand for new instruments is greater and greater.

F2-3: ARIF include both workhorse instruments that are used every day by researchers and racehorse instruments that represent the state of the art or are still developing.

F2-4: ARIF often depend on PhD-level technical research support staff for its proper operation and maintenance and to facilitate use by researchers. ARIF require highly specialized knowledge and training for proper operation and use . Nonspecialists increasingly need ARIF for their research and require dedicated personnel to provide expertise.

RECOMMENDATIONS

R2-1: The committee recommends the following definition of ARIF:

Advanced research instrumentation and facilities (ARIF) are instrumentation and facili ties housing collections of closely related or interacting instruments used for research and includes networks of sensors, data collections, and cyberinfrastructure. ARIF are distinguished from other types of instrumentation by being more commonly acquired by large-scale centers or research programs rather than individual investigators. The acquisition of ARIF by scientists often requires a substantial institutional commitment, depends on high-level decision-making at institutions and federal agencies, and is often managed by institutions. Furthermore, the advanced nature of ARIF often requires ex pert PhD-level technical research support staff for its operation and maintenance.

R2-2: Continued and vigorous federal investment in ARIF is essential to enable cutting-edge research in the future.

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HOW to Find Research Instruments

Books about research.

Information Literacy Coordinator

What are Research Instruments?

Research instruments are tools used to collect, measure, and analyze data related to your subject.

Research instruments can be  tests ,  surveys ,  scales ,  questionnaires , or even  checklists .

To assure the strength of your study, it is important to use previously validated instruments!

Finding Research Instruments

Sage Research Methods

This database contains information suited to all levels of researchers, from undergrads starting their first projects to the most senior faculty. It contains books, reference works, case studies, sample datasets, and videos. There is everything a researcher needs to design and execute a research project. 

You can explore the Methods Map in this database for guidance on:

• Designing a research project
• Quantitative methods design
• Qualitative methods design
• The practice of data analysis
• and more...

PsycINFO 1887-Current (EbscoHost)  

• This APA database contains useful information on Tests & Measures.                                                                     
• In searching, opt for the Tests & Measures selection to retrieve articles with relevant tests and measures
• Also refer to this LINK for more details about using PsycInfo
• Link to some educational resources on research instruments
• Selecting, developing, and evaluating research instruments

BOOKS from the ZU Library

Developing Research Instruments

Suggested sources of information:

• Electronic Questionnaires Design and Implementation
• Fundamental issues in questionnaire design

Instrument Development : Sage Research Methods                                     

Tips for developing and testing questionnaires

Using Cronbach’s Alpha When Developing and Reporting Research Instruments

• Magowe, M. K. M. (2012). Procedures for an instrument development study : The Botswana experience: Research instrument development procedures.  International Nursing Review,  59 (2), 281-288.  https://doi.org/10.1111/j.1466-7657.2011.00950.x
• Zhang, H., & Schuster, T. (2018). Questionnaire instrument development in primary health care research : A plea for the use of Bayesian inference.  Canadian Family Physician,  64 (9), 699-700.

Assessing the Reliability and Validity of Research Instruments

It is important to assess an instrument's validity and reliability before you try to obtain its full text.

• Open  this link  for information on  How to Determine the Validity and Reliability of an Instrument
• Article: Mohamad, M. M., Sulaiman, N. L., Sern, L. C., & Salleh, K. M. (2015). Measuring the validity and reliability of research instruments.  Procedia-Social and Behavioral Sciences ,  204 , 164-171.  https://doi.org/10.1016/j.sbspro.2015.08.129
• Chapter: Stapleton, L. M. (2019). In Hancock G. R., Stapleton L. M. and Mueller R. O.(Eds.),  The Reviewer’s guide to quantitative methods in the social sciences   (2nd ed.). Routledge. https://doi.org/10.4324/9781315755649. Chapter 35

Where you find that data depends on whether the instrument is "published" or "unpublished." 

Published Instruments

Published means commercially published, and that the instrument is typically available for sale. you can find reviews of many published instruments, including validity and reliability data, in  mental measurements yearbook , unpublished instruments, unpublished means that the instrument has not been commercially published.  if the instrument is   unpublished ,   contact the author directly., you may be able to find the full text of unpublished instruments using the  library's databases..

• If you find the full text, read the  permission terms  to determine if it is available for reuse or if you will need to contact the author/publisher.
• Look for the author's email address or phone number to contact them, also letting them know that you are a student.
• If the email bounces back or phone number doesn't work, search for their institution affiliation as this may lead to their contact information. 
• Ask your professor or  a librarian  for help! They might be able to help. 
• If you have tried all of the above and still cannot locate the author, see if the author has any co-authors (in other papers) that you can contact.
• Contact authors of articles that mention the instrument you are looking for, and ask them how they obtained permission.
• Last Updated: Aug 31, 2022 3:49 PM
• URL: https://zu.libguides.com/c.php?g=1210895

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Home » Survey Instruments – List and Their Uses

Survey Instruments – List and Their Uses

Table of Contents

Survey Instruments

Definition:

Survey instruments are tools used to collect data from a sample of individuals or a population. They typically consist of a series of questions designed to gather information on a particular topic or issue.

List of Survey Instruments

Types of Survey Instruments are as follows:

• Questionnaire : A questionnaire is a survey instrument consisting of a series of questions designed to gather information from a large number of respondents.
• Interview Schedule : An interview schedule is a survey instrument that is used to collect data from a small number of individuals through a face-to-face conversation or online communication.
• Focus Group Discussion Guide: A focus group discussion guide is a survey instrument used to facilitate a group discussion on a particular topic to collect opinions, attitudes, and perceptions of participants.
• Observation Checklist : An observation checklist is a survey instrument that is used to observe and record behaviors, events, or processes in a systematic and organized manner.
• Rating Scale: A rating scale is a survey instrument that is used to measure the extent to which an individual agrees or disagrees with a particular statement, or rates the quality of a product, service, or experience.
• Likert Scale: A Likert scale is a survey instrument that is used to measure attitudes, opinions, or perceptions of individuals towards a particular topic or statement.
• Semantic Differential Scale : A semantic differential scale is a survey instrument that is used to measure the connotative meaning of a particular concept, product, or service.
• Checklist: A checklist is a survey instrument that is used to systematically gather information on a specific topic or subject.
• Diaries and Logs: Diaries and logs are survey instruments that are used to record behaviors, activities, and experiences of participants over a period of time.
• Case Study: A case study is a survey instrument that is used to investigate a particular phenomenon, process, or event in-depth by analyzing the data from multiple sources.
• Ethnographic Field Notes : Ethnographic field notes are survey instruments used by ethnographers to record their observations and reflections during fieldwork, often in the form of detailed descriptions of people, places, and events.
• Psychometric Tests : Psychometric tests are survey instruments used to measure cognitive abilities, aptitudes, and personality traits.
• Exit Interviews : Exit interviews are survey instruments used to gather feedback from departing employees about their experiences working for a company, organization, or institution.
• Needs Assessment Surveys: Needs assessment surveys are survey instruments used to identify the needs, priorities, and preferences of a target population to inform program development and resource allocation.
• Community Needs Assessments : Community needs assessments are survey instruments used to gather information about the needs and priorities of a particular community, including its demographics, resources, and challenges.
• Performance Appraisal Forms: Performance appraisal forms are survey instruments used to evaluate the performance of employees against specific job-related criteria.
• Customer Needs Assessment Surveys: Customer needs assessment surveys are survey instruments used to identify the needs and preferences of customers to inform product development and marketing strategies.
• Learning Style Inventories : Learning style inventories are survey instruments used to identify an individual’s preferred learning style, such as visual, auditory, or kinesthetic.
• Team Performance Assessments: Team performance assessments are survey instruments used to evaluate the effectiveness of teams in achieving their goals and objectives.
• Organizational Climate Surveys: Organizational climate surveys are survey instruments used to gather information about the perceptions, attitudes, and values of employees towards their workplace.
• Employee Engagement Surveys: Employee engagement surveys are survey instruments used to measure the level of engagement, satisfaction, and commitment of employees towards their job and the organization.
• Self-Report Measures: Self-report measures are survey instruments used to gather information directly from participants about their own thoughts, feelings, and behaviors.
• Personality Inventories: Personality inventories are survey instruments used to measure individual differences in personality traits such as extroversion, conscientiousness, and openness to experience.
• Achievement Tests : Achievement tests are survey instruments used to measure the knowledge or skills acquired by individuals in a specific subject area or academic discipline.
• Attitude Scales: Attitude scales are survey instruments used to measure the degree to which an individual holds a particular attitude or belief towards a specific object, person, or idea.
• Customer Satisfaction Surveys: Customer satisfaction surveys are survey instruments used to gather feedback from customers about their experience with a product or service.
• Market Research Surveys: Market research surveys are survey instruments used to collect data on consumer behavior, market trends, and preferences to inform business decisions.
• Health Assessments: Health assessments are survey instruments used to gather information about an individual’s physical and mental health status, including medical history, symptoms, and lifestyle factors.
• Environmental Surveys: Environmental surveys are survey instruments used to gather information about environmental conditions and the impact of human activities on the natural world.
• Program Evaluation Surveys : Program evaluation surveys are survey instruments used to assess the effectiveness of programs and interventions in achieving their intended outcomes.
• Culture Assessments: Culture assessments are survey instruments used to gather information about the culture of an organization, including its values, beliefs, and practices.
• Customer Feedback Forms: Customer feedback forms are survey instruments used to gather feedback from customers about their experience with a product, service, or company.
• User Acceptance Testing (UAT) Forms: User acceptance testing (UAT) forms are survey instruments used to gather feedback from users about the functionality and usability of a software application or system.
• Stakeholder Surveys: Stakeholder surveys are survey instruments used to gather feedback from stakeholders, such as customers, employees, investors, and partners, about their perceptions and expectations of an organization or project.
• Social Network Analysis (SNA) Surveys: Social network analysis (SNA) surveys are survey instruments used to map and analyze social networks and relationships within a group or community.
• Leadership Assessments: Leadership assessments are survey instruments used to evaluate the leadership skills, styles, and behaviors of individuals in a leadership role.
• Exit Polls : Exit polls are survey instruments used to gather data on voting patterns and preferences in an election or referendum.
• Customer Loyalty Surveys : Customer loyalty surveys are survey instruments used to measure the level of loyalty and advocacy of customers towards a brand or company.
• Online Feedback Forms : Online feedback forms are survey instruments used to gather feedback from website visitors, customers, or users about their experience with a website, application, or digital product.
• Needs Analysis Surveys: Needs analysis surveys are survey instruments used to identify the training and development needs of employees or students to inform curriculum design and professional development programs.
• Career Assessments: Career assessments are survey instruments used to evaluate an individual’s interests, values, and skills to inform career decision-making and planning.
• Customer Perception Surveys: Customer perception surveys are survey instruments used to gather information about how customers perceive a product, service, or brand.
• Employee Satisfaction Surveys: Employee satisfaction surveys are survey instruments used to measure the level of job satisfaction, engagement, and motivation of employees.
• Conflict Resolution Assessments: Conflict resolution assessments are survey instruments used to identify the causes and sources of conflict in a group or organization and to inform conflict resolution strategies.
• Cultural Competence Assessments: Cultural competence assessments are survey instruments used to evaluate an individual’s ability to work effectively with people from diverse cultural backgrounds.
• Job Analysis Surveys: Job analysis surveys are survey instruments used to gather information about the tasks, responsibilities, and requirements of a particular job or position.
• Employee Turnover Surveys : Employee turnover surveys are survey instruments used to gather information about the reasons why employees leave a company or organization.
• Quality of Life Assessments: Quality of life assessments are survey instruments used to gather information about an individual’s physical, emotional, and social well-being.
• User Satisfaction Surveys: User satisfaction surveys are survey instruments used to gather feedback from users about their satisfaction with a product, service, or application.
• Data Collection Forms: Data collection forms are survey instruments used to gather information about a specific research question or topic, often used in quantitative research.
• Program Evaluation Forms: Program evaluation forms are survey instruments used to assess the effectiveness, efficiency, and impact of a program or intervention.
• Cultural Awareness Surveys: Cultural awareness surveys are survey instruments used to assess an individual’s knowledge and understanding of different cultures and customs.
• Employee Perception Surveys: Employee perception surveys are survey instruments used to gather information about how employees perceive their work environment, management, and colleagues.
• Leadership 360 Assessments: Leadership 360 assessments are survey instruments used to evaluate the leadership skills, styles, and behaviors of individuals from multiple perspectives, including self-assessment, peer feedback, and supervisor evaluation.
• Health Needs Assessments: Health needs assessments are survey instruments used to gather information about the health needs and priorities of a population to inform public health policies and programs.
• Social Capital Surveys: Social capital surveys are survey instruments used to measure the social networks and relationships within a community and their impact on social and economic outcomes.
• Psychosocial Assessments: Psychosocial assessments are survey instruments used to evaluate an individual’s psychological, social, and emotional well-being.
• Training Evaluation Forms: Training evaluation forms are survey instruments used to assess the effectiveness and impact of a training program on knowledge, skills, and behavior.
• Patient Satisfaction Surveys: Patient satisfaction surveys are survey instruments used to gather feedback from patients about their experience with healthcare services and providers.
• Program Needs Assessments : Program needs assessments are survey instruments used to identify the needs, goals, and expectations of stakeholders for a program or intervention.
• Community Needs Assessments: Community needs assessments are survey instruments used to gather information about the needs, challenges, and assets of a community to inform community development programs and policies.
• Environmental Assessments : Environmental assessments are survey instruments used to evaluate the environmental impact of a project, program, or policy.
• Stakeholder Analysis Surveys: Stakeholder analysis surveys are survey instruments used to identify and prioritize the needs, interests, and influence of stakeholders in a project or initiative.
• Performance Appraisal Forms: Performance appraisal forms are survey instruments used to evaluate the performance and contribution of employees to inform promotions, rewards, and career development plans.
• Consumer Behavior Surveys : Consumer behavior surveys are survey instruments used to gather information about the attitudes, beliefs, and behaviors of consumers towards products, brands, and services.
• Audience Feedback Forms : Audience feedback forms are survey instruments used to gather feedback from audience members about their experience with a performance, event, or media content.
• Market Research Surveys: Market research surveys are survey instruments used to gather information about market trends, customer preferences, and competition to inform business strategy and decision-making.
• Health Risk Assessments: Health risk assessments are survey instruments used to identify an individual’s health risks and to provide personalized recommendations for preventive care and lifestyle changes.
• Employee Engagement Surveys : Employee engagement surveys are survey instruments used to measure the level of employee engagement, commitment, and motivation in a company or organization.
• Social Impact Assessments: Social impact assessments are survey instruments used to evaluate the social, economic, and environmental impact of a project or policy on stakeholders and the community.
• Needs Assessment Forms : Needs assessment forms are survey instruments used to identify the needs, expectations, and priorities of stakeholders for a particular program, service, or project.
• Organizational Climate Surveys: Organizational climate surveys are survey instruments used to measure the overall culture, values, and climate of an organization, including the level of trust, communication, and support.
• Risk Assessment Forms: Risk assessment forms are survey instruments used to identify and evaluate potential risks associated with a project, program, or activity.
• Customer Service Surveys: Customer service surveys are survey instruments used to gather feedback from customers about the quality of customer service provided by a company or organization.
• Performance Evaluation Forms : Performance evaluation forms are survey instruments used to evaluate the performance and contribution of employees to inform promotions, rewards, and career development plans.
• Community Impact Assessments : Community impact assessments are survey instruments used to evaluate the social, economic, and environmental impact of a project or policy on the community.
• Health Status Surveys : Health status surveys are survey instruments used to gather information about an individual’s health status, including physical, mental, and emotional well-being.
• Organizational Effectiveness Surveys: Organizational effectiveness surveys are survey instruments used to measure the overall effectiveness and performance of an organization, including the alignment of goals, strategies, and outcomes.
• Program Implementation Surveys: Program implementation surveys are survey instruments used to evaluate the implementation process of a program or intervention, including the quality, fidelity, and sustainability.
• Social Support Surveys : Social support surveys are survey instruments used to measure the level of social support and connectedness within a community or group and their impact on health and well-being.

Survey Instruments in Research Methods

The following are some commonly used survey instruments in research methods:

• Questionnaires : A questionnaire is a set of standardized questions designed to collect information about a specific topic. Questionnaires can be administered in different ways, including in person, over the phone, or online.
• Interviews : Interviews involve asking participants a series of questions in a face-to-face or phone conversation. Interviews can be structured, semi-structured, or unstructured depending on the research question and the researcher’s goals.
• Surveys : Surveys are used to collect data from a large number of participants through self-report. Surveys can be administered through various mediums, including paper-based, phone-based, and online surveys.
• Focus Groups : A focus group is a qualitative research method where a group of individuals is brought together to discuss a particular topic. The goal is to gather in-depth information about participants’ perceptions, attitudes, and beliefs.
• Case Studies: A case study is an in-depth analysis of an individual, group, or organization. The researcher collects data through various methods, including interviews, observation, and document analysis.
• Observations : Observations involve watching participants in their natural setting and recording their behavior. Observations can be structured or unstructured, and the data collected can be qualitative or quantitative.

Survey Instruments in Qualitative Research

In qualitative research , survey instruments are used to gather data from participants through structured or semi-structured questionnaires. These instruments are used to gather information on a wide range of topics, including attitudes, beliefs, perceptions, experiences, and behaviors.

Here are some commonly used survey instruments in qualitative research:

• Focus groups
• Questionnaires
• Observation
• Document analysis

Survey Instruments in Quantitative Research

Survey instruments are commonly used in quantitative research to collect data from a large number of respondents. The following are some commonly used survey instruments:

• Self-Administered Surveys:
• Telephone Surveys
• Online Surveys
• Focus Groups
• Observations

Importance of Survey Instruments

Here are some reasons why survey instruments are important:

• Provide valuable insights : Survey instruments help researchers gather accurate data and provide valuable insights into various phenomena. Researchers can use the data collected through surveys to analyze trends, patterns, and relationships between variables, leading to a better understanding of the topic at hand.
• Measure changes over time: By using survey instruments, researchers can measure changes in attitudes, beliefs, or behaviors over time. This allows them to identify trends and patterns, which can inform policy decisions and interventions.
• Inform decision-making: Survey instruments can provide decision-makers with information on the opinions, preferences, and needs of a particular group. This information can be used to make informed decisions and to tailor programs and policies to meet the specific needs of a population.
• Cost-effective: Compared to other research methods, such as focus groups or in-depth interviews, survey instruments are relatively cost-effective. They can be administered to a large number of participants at once, and data can be collected and analyzed quickly and efficiently.
• Standardization : Survey instruments can be standardized to ensure that all participants are asked the same questions in the same way. This helps to ensure that the data collected is consistent and reliable.

Applications of Survey Instruments

The data collected through surveys can be used for various purposes, including:

• Market research : Surveys can be used to collect data on consumer preferences, habits, and opinions, which can help businesses make informed decisions about their products or services.
• Social research: Surveys can be used to collect data on social issues such as public opinion, political preferences, and attitudes towards social policies.
• Health research: Surveys can be used to collect data on health-related issues such as disease prevalence, risk factors, and health behaviors.
• Education research : Surveys can be used to collect data on education-related issues such as student satisfaction, teacher performance, and educational outcomes.
• Customer satisfaction: Surveys can be used to collect data on customer satisfaction, which can help businesses improve their products and services.
• Employee satisfaction : Surveys can be used to collect data on employee satisfaction, which can help employers improve their workplace policies and practices.
• Program evaluation : Surveys can be used to collect data on program outcomes and effectiveness, which can help organizations improve their programs.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

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Finding Research Instruments, Surveys, and Tests: Home

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What are Research Instruments

A research instrument is a survey, questionnaire, test, scale, rating, or tool designed to measure the variable(s), characteristic(s), or information of interest, often a behavioral or psychological characteristic. Research instruments can be helpful tools to your research study.

"Careful planning for data collection can help with setting realistic goals. Data collection instrumentation, such as surveys, physiologic measures (blood pressure or temperature), or interview guides, must be identified and described. Using previously validated collection instruments can save time and increase the study's credibility. Once the data collection procedure has been determined, a time line for completion should be established." (Pierce, 2009, p. 159)

• Pierce, L.L. (2009). Twelve steps for success in the nursing research journey. Journal of Continuing Education in Nursing 40(4), 154-162.

A research instrument is developed as a method of data generation by researchers and information about the research instrument is shared in order to establish the credibility and validity of the method. Whether other researchers may use the research instrument is the decision of the original author-researchers. They may make it publicly available for free or for a price or they may not share it at all. Sources about research instruments have a purpose of describing the instrument to inform. Sources may or may not provide the instrument itself or the contact information of the author-researcher. The onus is on the reader-researcher to try to find the instrument itself or to contact the author-researcher to request permission for its use, if necessary.

How to choose the right one?

Are you trying to find background information about a research instrument? Or are you trying to find and obtain an actual copy of the instrument?

If you need information about a research instrument, what kind of information do you need? Do you need information on the structure of the instrument, its content, its development, its psychometric reliability or validity? What do you need?

If you plan to obtain an actual copy of the instrument to use in research, you need to be concerned not only with obtaining the instrument, but also obtaining permission to use the instrument. Research instruments may be copyrighted. To obtain permission, contact the copyright holder in writing (print or email).

If someone posts a published test or instrument without the permission of the copyright holder, they may be violating copyright and could be legally liable. 

What are you trying to measure? For example, if you are studying depression, are you trying to measure the duration of depression, the intensity of depression, the change over time of the episodes, … what? The instrument must measure what you need or it is useless to you.

Factors to consider when selecting an instrument are • Well-tested factorial structure, validity & reliability • Availability of supportive materials and technology for entering, analyzing and interpreting results • Availability of normative data as a reference for evaluating, interpreting, or placing in context individual test scores • Applicable to wide range of participants • Can also be used as personal development tool/exercise • User-friendliness & administrative ease • Availability; can you obtain it? • Does it require permission from the owner to use it? • Financial cost • Amount of time required

Check the validity and reliability of tests and instruments. Do they really measure what they claim to measure? Do they measure consistently over time, with different research subjects and ethnic groups, and after repeated use? Research articles that used the test will often include reliability and validity data.

How Locate Instrument

Realize that searching for an instrument may take a lot of time. They may be published in a book or article on a particular subject. They be published and described in a dissertation. They may posted on the Internet and freely available. A specific instrument may be found in multiple publications and have been used for a long time. Or it may be new and only described in a few places. It may only be available by contacting the person who developed it, who may or may not respond to your inquiry in a timely manner.

There are a variety of sources that may used to search for research instruments. They include books, databases, Internet search engines, Web sites, journal articles, and dissertations.

A few key sources and search tips are listed in this guide.

Permission to Use the Test

If you plan to obtain an actual copy of the instrument to use in research, you need to be concerned not only with obtaining the instrument, but also obtaining permission to use the instrument. Research instruments are copyrighted. To obtain permission, contact the copyright holder to obtain permission in writing (print or email). Written permission is a record that you obtained permission.

It is a good idea to have them state in wiritng that they are indeed the copyright holder and that they grant you permission to use the instrument. If you wish to publish the actual instrument in your paper, get permission for that, too. You may write about the instrument without obtaining permission. (But remember to cite it!)

If someone posts a published test or instrument without the permission of the copyright holder, they are violating copyright and could be legally liable. 

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Understanding and Evaluating Survey Research

A variety of methodologic approaches exist for individuals interested in conducting research. Selection of a research approach depends on a number of factors, including the purpose of the research, the type of research questions to be answered, and the availability of resources. The purpose of this article is to describe survey research as one approach to the conduct of research so that the reader can critically evaluate the appropriateness of the conclusions from studies employing survey research.

SURVEY RESEARCH

Survey research is defined as "the collection of information from a sample of individuals through their responses to questions" ( Check & Schutt, 2012, p. 160 ). This type of research allows for a variety of methods to recruit participants, collect data, and utilize various methods of instrumentation. Survey research can use quantitative research strategies (e.g., using questionnaires with numerically rated items), qualitative research strategies (e.g., using open-ended questions), or both strategies (i.e., mixed methods). As it is often used to describe and explore human behavior, surveys are therefore frequently used in social and psychological research ( Singleton & Straits, 2009 ).

Information has been obtained from individuals and groups through the use of survey research for decades. It can range from asking a few targeted questions of individuals on a street corner to obtain information related to behaviors and preferences, to a more rigorous study using multiple valid and reliable instruments. Common examples of less rigorous surveys include marketing or political surveys of consumer patterns and public opinion polls.

Survey research has historically included large population-based data collection. The primary purpose of this type of survey research was to obtain information describing characteristics of a large sample of individuals of interest relatively quickly. Large census surveys obtaining information reflecting demographic and personal characteristics and consumer feedback surveys are prime examples. These surveys were often provided through the mail and were intended to describe demographic characteristics of individuals or obtain opinions on which to base programs or products for a population or group.

More recently, survey research has developed into a rigorous approach to research, with scientifically tested strategies detailing who to include (representative sample), what and how to distribute (survey method), and when to initiate the survey and follow up with nonresponders (reducing nonresponse error), in order to ensure a high-quality research process and outcome. Currently, the term "survey" can reflect a range of research aims, sampling and recruitment strategies, data collection instruments, and methods of survey administration.

Given this range of options in the conduct of survey research, it is imperative for the consumer/reader of survey research to understand the potential for bias in survey research as well as the tested techniques for reducing bias, in order to draw appropriate conclusions about the information reported in this manner. Common types of error in research, along with the sources of error and strategies for reducing error as described throughout this article, are summarized in the Table .

Sources of Error in Survey Research and Strategies to Reduce Error

The goal of sampling strategies in survey research is to obtain a sufficient sample that is representative of the population of interest. It is often not feasible to collect data from an entire population of interest (e.g., all individuals with lung cancer); therefore, a subset of the population or sample is used to estimate the population responses (e.g., individuals with lung cancer currently receiving treatment). A large random sample increases the likelihood that the responses from the sample will accurately reflect the entire population. In order to accurately draw conclusions about the population, the sample must include individuals with characteristics similar to the population.

It is therefore necessary to correctly identify the population of interest (e.g., individuals with lung cancer currently receiving treatment vs. all individuals with lung cancer). The sample will ideally include individuals who reflect the intended population in terms of all characteristics of the population (e.g., sex, socioeconomic characteristics, symptom experience) and contain a similar distribution of individuals with those characteristics. As discussed by Mady Stovall beginning on page 162, Fujimori et al. ( 2014 ), for example, were interested in the population of oncologists. The authors obtained a sample of oncologists from two hospitals in Japan. These participants may or may not have similar characteristics to all oncologists in Japan.

Participant recruitment strategies can affect the adequacy and representativeness of the sample obtained. Using diverse recruitment strategies can help improve the size of the sample and help ensure adequate coverage of the intended population. For example, if a survey researcher intends to obtain a sample of individuals with breast cancer representative of all individuals with breast cancer in the United States, the researcher would want to use recruitment strategies that would recruit both women and men, individuals from rural and urban settings, individuals receiving and not receiving active treatment, and so on. Because of the difficulty in obtaining samples representative of a large population, researchers may focus the population of interest to a subset of individuals (e.g., women with stage III or IV breast cancer). Large census surveys require extremely large samples to adequately represent the characteristics of the population because they are intended to represent the entire population.

DATA COLLECTION METHODS

Survey research may use a variety of data collection methods with the most common being questionnaires and interviews. Questionnaires may be self-administered or administered by a professional, may be administered individually or in a group, and typically include a series of items reflecting the research aims. Questionnaires may include demographic questions in addition to valid and reliable research instruments ( Costanzo, Stawski, Ryff, Coe, & Almeida, 2012 ; DuBenske et al., 2014 ; Ponto, Ellington, Mellon, & Beck, 2010 ). It is helpful to the reader when authors describe the contents of the survey questionnaire so that the reader can interpret and evaluate the potential for errors of validity (e.g., items or instruments that do not measure what they are intended to measure) and reliability (e.g., items or instruments that do not measure a construct consistently). Helpful examples of articles that describe the survey instruments exist in the literature ( Buerhaus et al., 2012 ).

Questionnaires may be in paper form and mailed to participants, delivered in an electronic format via email or an Internet-based program such as SurveyMonkey, or a combination of both, giving the participant the option to choose which method is preferred ( Ponto et al., 2010 ). Using a combination of methods of survey administration can help to ensure better sample coverage (i.e., all individuals in the population having a chance of inclusion in the sample) therefore reducing coverage error ( Dillman, Smyth, & Christian, 2014 ; Singleton & Straits, 2009 ). For example, if a researcher were to only use an Internet-delivered questionnaire, individuals without access to a computer would be excluded from participation. Self-administered mailed, group, or Internet-based questionnaires are relatively low cost and practical for a large sample ( Check & Schutt, 2012 ).

Dillman et al. ( 2014 ) have described and tested a tailored design method for survey research. Improving the visual appeal and graphics of surveys by using a font size appropriate for the respondents, ordering items logically without creating unintended response bias, and arranging items clearly on each page can increase the response rate to electronic questionnaires. Attending to these and other issues in electronic questionnaires can help reduce measurement error (i.e., lack of validity or reliability) and help ensure a better response rate.

Conducting interviews is another approach to data collection used in survey research. Interviews may be conducted by phone, computer, or in person and have the benefit of visually identifying the nonverbal response(s) of the interviewee and subsequently being able to clarify the intended question. An interviewer can use probing comments to obtain more information about a question or topic and can request clarification of an unclear response ( Singleton & Straits, 2009 ). Interviews can be costly and time intensive, and therefore are relatively impractical for large samples.

Some authors advocate for using mixed methods for survey research when no one method is adequate to address the planned research aims, to reduce the potential for measurement and non-response error, and to better tailor the study methods to the intended sample ( Dillman et al., 2014 ; Singleton & Straits, 2009 ). For example, a mixed methods survey research approach may begin with distributing a questionnaire and following up with telephone interviews to clarify unclear survey responses ( Singleton & Straits, 2009 ). Mixed methods might also be used when visual or auditory deficits preclude an individual from completing a questionnaire or participating in an interview.

FUJIMORI ET AL.: SURVEY RESEARCH

Fujimori et al. ( 2014 ) described the use of survey research in a study of the effect of communication skills training for oncologists on oncologist and patient outcomes (e.g., oncologist’s performance and confidence and patient’s distress, satisfaction, and trust). A sample of 30 oncologists from two hospitals was obtained and though the authors provided a power analysis concluding an adequate number of oncologist participants to detect differences between baseline and follow-up scores, the conclusions of the study may not be generalizable to a broader population of oncologists. Oncologists were randomized to either an intervention group (i.e., communication skills training) or a control group (i.e., no training).

Fujimori et al. ( 2014 ) chose a quantitative approach to collect data from oncologist and patient participants regarding the study outcome variables. Self-report numeric ratings were used to measure oncologist confidence and patient distress, satisfaction, and trust. Oncologist confidence was measured using two instruments each using 10-point Likert rating scales. The Hospital Anxiety and Depression Scale (HADS) was used to measure patient distress and has demonstrated validity and reliability in a number of populations including individuals with cancer ( Bjelland, Dahl, Haug, & Neckelmann, 2002 ). Patient satisfaction and trust were measured using 0 to 10 numeric rating scales. Numeric observer ratings were used to measure oncologist performance of communication skills based on a videotaped interaction with a standardized patient. Participants completed the same questionnaires at baseline and follow-up.

The authors clearly describe what data were collected from all participants. Providing additional information about the manner in which questionnaires were distributed (i.e., electronic, mail), the setting in which data were collected (e.g., home, clinic), and the design of the survey instruments (e.g., visual appeal, format, content, arrangement of items) would assist the reader in drawing conclusions about the potential for measurement and nonresponse error. The authors describe conducting a follow-up phone call or mail inquiry for nonresponders, using the Dillman et al. ( 2014 ) tailored design for survey research follow-up may have reduced nonresponse error.

CONCLUSIONS

Survey research is a useful and legitimate approach to research that has clear benefits in helping to describe and explore variables and constructs of interest. Survey research, like all research, has the potential for a variety of sources of error, but several strategies exist to reduce the potential for error. Advanced practitioners aware of the potential sources of error and strategies to improve survey research can better determine how and whether the conclusions from a survey research study apply to practice.

The author has no potential conflicts of interest to disclose.

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The Researcher as an Instrument

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In qualitative research, there are many different sources of data. Qualitative research data are collected using many different methods. Interestingly, one of these data collection methods is the researcher himself or herself. This is the reason why most experts consider the researcher as an instrument. The question always asked is “What does it really mean?” This chapter explains what it is and what is expected from the researcher in his or her role as an instrument throughout a qualitative research study. The ethical considerations pertaining to this important role are also discussed. This chapter is meant to bring this important role to everyone’s awareness so that rigor in qualitative research can be fostered.

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Wa-Mbaleka, S. (2020). The Researcher as an Instrument. In: Costa, A., Reis, L., Moreira, A. (eds) Computer Supported Qualitative Research. WCQR 2019. Advances in Intelligent Systems and Computing, vol 1068. Springer, Cham. https://doi.org/10.1007/978-3-030-31787-4_3

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ORIGINAL RESEARCH article

This article is part of the research topic.

Diabetes Complications in Children and Adolescents: From Low-Resource to Technology-Advanced Countries

Neurological Dysfunction Screening in a Cohort of Adolescents with Type 1 Diabetes: a Six-Year Follow-Up Authors information Provisionally Accepted

• 1 Department of Public Health and Pediatric Sciences, School of Medicine, University of Turin, Italy
• 2 Child and Adolescent Neuropsychiatry Unit, Department of Sciences of Public Health and Pediatrics, University of Turin, Italy
• 3 Department of Health and Science, University of Eastern Piedmont, Italy

The final, formatted version of the article will be published soon.

Diabetic neuropathy (DN) is one of the most insidious microvascular complications in patients with type 1 diabetes (T1DM) and initial signs may appear during childhood. The aim of this study is to evaluate associations between the Nerve Conduction Studies (NCS) outcomes at enrollment with neuropathy screening questionnaires performed six years later in a cohort of asymptomatic adolescents followed up until early adulthood, affected by T1DM.We performed NCS in a cohort of seventy-two adolescents with T1DM and eighteen healthy controls. Six years later, screening questionnaires for DN were proposed: Michigan Neuropathy Screening Instrument (MNSI, specific for symptoms of somatic dysfunction), Composite Autonomic Symptom Score 31 (COMPASS 31, specific for abnormalities of the autonomic component) and Clarke questionnaire (perception of hypoglycemia). Thirty-two TD1M subjects agreed to participate in the follow-up; main clinical-metabolic parameters, including the number of episodes of hypoglycemia in the past twelve months, were collected.11.8% of subjects showed changes compatible with DN through the MNSI questionnaire, while 41% declared a reduced perception of hypoglycemia on the Clarke questionnaire. No significant correlation was observed between the clinical-metabolic parameters or altered response to NCS and scores of MNSI and COMPASS 31 questionnaires. On the other hand, an association was observed between NCS abnormalities and a high number of hypoglycemic events after six years (97-fold increased risk, P=0.009).The frequency of somatic alterations in the study population is 11.8%, whereas the frequency of symptoms correlated with autonomic damage is about 41%. An autonomic impairment recorded at NCS may represent a six-year risk factor for increased hypoglycemic episodes, even if more extensive studies are needed to investigate this possible relationship further.

Keywords: diabetes, Adolescent, Hypoglycemia, nerve conduction study, Diabetic neuropathy

Received: 31 Oct 2023; Accepted: 22 Apr 2024.

Copyright: © 2024 Tinti, Canavese, Nobili, Marcotulli, Daniele, Rabbone and de Sanctis. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: MD, PhD. Davide Tinti, Department of Public Health and Pediatric Sciences, School of Medicine, University of Turin, Turin, Italy

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As President Joe Biden and the new Republican majority in the U.S. House of Representatives face off over the debt ceiling and government spending, more Americans say they have favorable than unfavorable opinions of many agencies and departments of the federal government.

Americans view 14 of 16 federal agencies more favorably than unfavorably, according to a survey of 10,701 adults conducted March 13-19 by Pew Research Center. Of those 14 agencies, 11 have net favorable ratings of 15 points or more.

Topping the list are the National Park Service (81% favorable), the U.S. Postal Service (77%) and NASA (74%). Smaller majorities have favorable impressions of other agencies, including the Social Security Administration (61% favorable) and the Department of Health and Human Services (HHS, 55%).

Americans have mixed views of the Department of Education (45% favorable, 47% unfavorable) and the Federal Reserve (43% favorable, 37% unfavorable, 20% unsure). The least popular federal agency of the 16 asked about is the IRS. About half of Americans (51%) have an unfavorable opinion of this agency, while 42% have a favorable view.

Pew Research Center regularly conducts surveys to gauge the public’s attitudes about the federal government, including government agencies and departments. For this analysis, we surveyed 10,701 adults from March 13-19, 2023. Everyone who took part in this survey is a member of the Center’s American Trends Panel (ATP), an online survey panel that is recruited through national, random sampling of residential addresses. This way nearly all U.S. adults have a chance of selection. The survey is weighted to be representative of the U.S. adult population by gender, race, ethnicity, partisan affiliation, education and other categories. Read more about the ATP’s methodology .

Here are the questions used for the analysis and its methodology .

Agencies viewed favorably in this online survey were also among the most favorably viewed in past Pew Research Center surveys conducted by telephone. However, because of differences in survey mode and question wording, the specific percentages from past telephone surveys and this web survey are not directly comparable. (Refer to the drop-down box below for more details.)

This survey is the first time Pew Research Center has measured the public’s attitudes about federal government agencies on our online American Trends Panel . Previous surveys measuring views of federal agencies were conducted by telephone.

The findings in the current survey are not directly comparable with those past surveys for two reasons:

1. This survey uses different question wording than past telephone surveys. Telephone respondents had to volunteer that they did not have an opinion about an agency, while online survey respondents receive an explicit “not sure” response option. This generally results in a larger share of respondents declining to offer an opinion.

2. Surveys conducted by telephone or online often produce different results because respondents at times answer similar questions differently across modes. This is called a “mode effect.”

These two factors mean that point estimates (for instance, the share of respondents expressing a favorable opinion about a single agency between this survey and a prior phone survey) should not be directly compared to measure change over time, as the differences between the two would conflate mode and question wording differences with change over time. Despite this, some broad comparisons can be made: For example, if a wide partisan gap is evident for one agency that was not apparent in past surveys, whereas the partisan gap is relatively stable for other agencies, that change is likely not only a result of the transition from telephone to online polling.

Republicans have mostly negative views of the CDC, Department of Education

There are wide partisan gaps in Americans’ views of federal agencies. Democrats and those who lean toward the Democratic Party hold consistently favorable views of all 16 agencies asked about, while Republicans and those who lean toward the Republican Party express more unfavorable than favorable views for 10 of the agencies.

The partisan divisions in favorability are deepest for the Centers for Disease Control and Prevention, or CDC (80% favorable among Democrats vs. 31% among Republicans); the Environmental Protection Agency, or EPA (74% vs. 36%); and the Department of Education (62% vs. 29%). Republicans’ and Democrats’ views are also deeply divided over the Department of Transportation, HHS, the FBI, the IRS, the Federal Reserve and other agencies.

In contrast, there is more partisan agreement on the Department of Veterans Affairs (56% favorable among Republicans vs. 57% among Democrats); the National Park Service (81% vs. 84%); the Postal Service (73% vs. 82%); and NASA (71% vs. 79%). Among Democrats, the CDC and EPA receive some of the highest net favorability ratings. Eight-in-ten Democrats give a favorable rating to the CDC compared with 15% who see the agency unfavorably – for a 65 percentage point net advantage. For the EPA, 74% of Democrats see the agency favorably – 62 points more than the share who see it unfavorably. Democrats view the IRS least favorably of the 16 federal agencies: They are only 13 percentage points more likely to view it favorably than unfavorably (53% vs. 40%).

Republicans are much less favorable toward most federal agencies than Democrats. However, the agencies that Republicans feel most favorably toward are the National Park Service (72-point net favorability), NASA (58 points) and the Postal Service (48 points).

While it is not possible to make direct percentage point comparisons to past surveys due to a shift in survey mode, Republicans have substantially more negative than positive views of a majority of the agencies today than in the past.

Republicans’ negative opinions of the CDC, in particular, appear to reflect a shift since the early days of the coronavirus outbreak . Past Pew Research Center surveys have shown that Republicans have been especially critical of the CDC’s handling of the virus. Last September , just 32% of Republicans said that public health officials such as those at the CDC had done an excellent or good job in responding to the COVID-19 outbreak, compared with 73% of Democrats. In March 2020, at the start of the pandemic, large majorities of Republicans (84%) and Democrats (74%) had expressed positive views of the CDC’s performance.

Note: Here are the questions used for the analysis and its methodology .

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J. Baxter Oliphant is a senior researcher focusing on politics at Pew Research Center

Andy Cerda is a research assistant focusing on politics at Pew Research Center

Americans rate their federal, state and local governments less positively than a few years ago

Nearly three-quarters of americans say it would be ‘too risky’ to give presidents more power, the changing face of america’s veteran population, americans’ dismal views of the nation’s politics, what the data says about food stamps in the u.s., most popular.

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• Open access
• Published: 20 April 2024

Postoperative pain after single-visit root canal treatments in necrotic teeth comparing instruments’ kinematics and apical instrumentation limits – a prospective randomized multicenter clinical trial

• Ricardo Machado 1 ,
• Guilherme Moreira 2 ,
• Daniel Comparin 3 ,
• Arthur Pimentel Barroso 4 ,
• Jaqueline Nascimento 5 ,
• Caio Cézar Randi Ferraz 4 ,
• Sérgio Aparecido Ignácio 6 ,
• Lucas da Fonseca Roberti Garcia 7 ,
• Rodrigo Rodrigues Amaral 8 ,
• David Shadid 1 &
• Ulisses Xavier da Silva Neto 5  

BMC Oral Health volume  24 , Article number:  481 ( 2024 ) Cite this article

255 Accesses

Metrics details

This prospective randomized multicenter clinical trial (PRMCT) investigated postoperative pain after single-visit root canal treatments in teeth affected by pulp necrosis (PN), and asymptomatic apical periodontitis (AAP) (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas) comparing different instruments' kinematics and apical instrumentation limits.

Before chemomechanical preparation, 240 patients/teeth were randomly distributed into four groups ( n  = 60) according to the instruments' kinematics (rotary or reciprocating) and apical instrumentation limits (with or without intentional foraminal enlargement [IFE]). After that, specimens were submitted to the same irrigation and obturation techniques, and the patients were referred to undergo the definitive restorations. No medication was prescribed, but the patients were instructed to take either paracetamol (750 mg every 6 h for three days) or ibuprofen (600 mg every 6 h for three days) in pain cases. Postoperative pain incidence and levels were assessed at 24-, 48-, and 72 h following treatment completion according to a verbal rating scale (VRS) following a score. The Kolmogorov–Smirnov test was applied to assess the normality of the data. Mann–Whitney U, Chi-square, Friedman's ANOVA, and Friedman's multiple 2 to 2 comparison tests were employed to identify potential significant statistical differences among the variables in the study groups ( P  < .05).

Significant statistical differences were only observed among the groups considering tooth, periradicular status, and the occurrence of overfilling (sealer extrusion) ( P  < 0.00). Patients with teeth instrumented through rotary kinematics and without IFE experienced lower rates of postoperative pain; however, this difference was relevant only at 24 h ( P  < 0.05).

Conclusions

Postoperative pain was lower after using a rotary file system (Profile 04) inserted up to the apical constriction (AC). However, this finding was just statistically meaningful at 24 h.

Trial registration

This PRMCT was approved by the Human Research Ethics Committee of the Paranaense University – UNIPAR, Francisco Beltrão, PR, Brazil (CAAE. 46,774,621.6.0000.0109) on 02/09/2021. It was registered at The Brazilian Registry of Clinical Trials – ReBEC (RBR-3r967t) on 01/06/2023, was performed according to the Principles of the Helsinki Declaration and is reported following the Consolidated Standards of Reporting Trials Statement.

Peer Review reports

Root canal treatment is based on cleaning, shaping, and filling the root canal system (RCS) to maintain or restore the health of periapical tissues [ 1 ]. Chemomechanical preparation [ 2 ], and intracanal dressing [ 3 ] (when used) are the main responsible for the disinfection process; nevertheless, the complete eradication of endodontic infection is unfeasible due to the following primary and synergic factors: i) the anatomical complexity of the RCS [ 4 ], and; ii) the virulence and resistance of endodontic pathogens, mainly when they are organized in biofilms [ 5 ].

Efficient biomechanical preparation is only achieved by determining a correct apical limit, defined as the distance between two opposite external and internal points/surfaces. While the external point is located on the coronary surface, the internal point corresponds to the greatest depth reached by the endodontic files used during the root canal shaping [ 6 , 7 ].

Among the main factors associated with the endodontic prognosis, determining apical instrumentation limits close to the cement-dentin-canal junction plays a role in obtaining favorable outcomes [ 7 , 8 , 9 , 10 , 11 , 12 ]. Therefore, despite different philosophical trends [ 13 , 14 ], scientific evidence recommends the working length be set at 0.5–1.0 mm from the major apical foramina, i.e., at the apical constriction (AC). This recommendation is based on sound wound healing principles – the severance of the tissue in that area will create the smallest possible wound – the less tissue to heal, the better the cure [ 7 ].

However, microbiological analyses performed through molecular methods have revealed the existence of bacterial biofilms in the apical foramen (AF) [ 5 ], which represents the main reason for investigating the effects of intentional foraminal enlargement (IFE) on the prognosis of endodontic therapy [ 15 ].

IFE consists of widening the AF using an endodontic file larger than the anatomic constriction at the foramen level or beyond [ 14 , 16 , 17 ]. IFE aims to reduce bacterial content by eliminating contaminated cementum and dentin through the mechanical widening of the AF [ 14 ]. This approach has been investigated in past studies, which signaled the possibility of a greater bacterial reduction in the foraminal region, potentially associated with improved endodontic prognosis. The available clinical evidence reports a success rate of up to 96% using this approach [ 18 , 19 ]. Nonetheless, IFE may result in a more significant amount of debris being extruded [ 20 ] – an undesirable event potentially associated with postoperative pain from the induction of a local inflammatory process influenced by several factors, such as irrigation solutions or techniques [ 21 ], instrument's kinematics [ 22 ], as well as apical instrumentation limits [ 23 ].

To date, no study has been performed to investigate the incidence and levels of postoperative pain after single-visit root canal treatments in teeth affected by pulp necrosis (PN), and asymptomatic apical periodontitis (AAP) (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas) comparing different instruments' kinematics (rotary or reciprocating) and apical instrumentation limits (with or without IFE). Accordingly, this prospective randomized multicenter clinical trial (PRMCT) was planned to investigate these factors. The null hypothesis established was that the instruments' kinematics and apical instrumentation limits would not affect the level and frequency of postoperative pain after single-visit root canal treatments in teeth with the clinical features described above.

This PRMCT was approved by the Human Research Ethics Committee of the Paranaense University – UNIPAR, Francisco Beltrão, PR, Brazil (CAAE. 46,774,621.6.0000.0109) on 02/09/2021. It was registered at The Brazilian Registry of Clinical Trials – ReBEC (RBR-3r967t) on 01/06/2023, was performed according to the Principles of the Helsinki Declaration [ 24 ], and is reported following the Consolidated Standards of Reporting Trials Statement [ 25 ]. The patients received information about postoperative care, clinical and radiographic exams, and alternative treatment options. All of them (or caregivers for those under 18) were given details about the study and treatment protocol, and informed consent was obtained. Consent for publication was not applicable to this research.

Sample size calculation

The sample size for this research was determined after a pilot study, in which less than 5% of patients reported significant postoperative pain (acute, severe, or moderate) after the treatment. Considering a confidence level of 95% and a maximum margin of error of 5.5%, the proportion-sampling method determined a sample size of 240 patients/teeth (60 per group) [ 26 ].

Case selection

This PRMCT was conducted on individuals aged 14 to 86 (mean ± SD = 40.39 ± 6.35) between July 2022 and July 2023. The adopted inclusion criteria were teeth affected by pulp necrosis, and AAP (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas), physiological periodontal probing depth (≤ 3 mm), previously submitted to the endodontic access, and subsequently referred for root canal treatment. As all teeth had been previously open, the diagnosis of PN was based on the following criteria/information/signs: i) all the referral letters provided by the indicators showed this diagnosis (PN); ii) some teeth presented chronic apical periodontitis visible radiographically; iii) all teeth presented negative responses to the cold (EndoIce, Coltene/Whaledent Inc., Cuyahoga Falls, Ohio, United States) and electric pulp tests (Diagnostic Unit, Sybron Endo, Orange, United States of America), and; iv) all treated teeth present complete absence of bleeding during the treatment. Exclusion criteria concerning personal, behavioral, emotional, and systemic conditions of the patients were: recent use of anti-inflammatories, analgesics, or antibiotics; presence of trismus and systemic diseases; intolerance to the use of non-steroidal anti-inflammatory drugs; lack of cooperation, and pregnancy. Exclusion criteria considering odontogenic factors were: teeth affected by root resorptions, associated with sinus tracts, presenting periodontal compromise (probing depth > 3 mm), previously traumatized, incorrectly positioned (malocclusion), and under occlusal trauma [ 26 ]. Each patient had only one tooth included in the study. Four experienced endodontists performed the treatments in specialized clinics following a previously written descriptive protocol for each study group [ 27 ].

Randomization, allocation concealment of the instrumentation systems, and pretreatment instructions

The randomization process was done using a table created by the Sealed Envelope™ software ( www.sealedenvelope.com – Exmouth House, London, UK). The task was carried out by an investigator not involved in the present research. A list of 240 numbers was prepared and distributed into three blocks (80 per group). First, each number corresponding to a study group was placed in a numbered, opaque, and sealed envelope. When a patient was deemed eligible, the envelope was opened before the root canal treatment to determine the necessary clinical procedures. This way, the four clinicians performed 15 root canal treatments that composed the specimens of each study group (n. 60), totaling 240 patients/teeth (total sample). Based on the previously stated inclusion and exclusion criteria, Fig.  1 exposes the study flow chart.

Study flowchart

Treatment protocol

Following clinical and radiographic examinations of each patient, the tooth was anesthetized using 2% mepivacaine with epinephrine 1:100.000 (Mepiadre; DFL Indústria e Comércio S.A., Rio de Janeiro, RJ, Brazil). After placing and disinfecting the rubber dam, the temporary restoration was removed using nos. 1014 or 1016 HL burs (KG Sorensen, Barueri, SP, Brazil). After reaching the pulp chamber, 5 mL of 2.5% sodium hypochlorite (NaOCl) (Fórmula & Ação, São Paulo, SP, Brazil) was used for irrigation by using a NaviTip 31 G needle (Ultradent, South Jordan, UT, United States of America). Initial exploration of the root canal was performed with no. 10 or 15 K-FlexoFiles (Dentsply-Maillefer, Ballaigues, Switzerland). The cervical and middle thirds were prepared with Gates-Glidden drills (Dentsply-Maillefer) activated by an endodontic electric motor (X-Smart Plus, Dentsply-Maillefer) at 800 rpm. Before the chemomechanical preparation, anatomical diameters of the AF and AC were identified through K-FlexoFiles in ascending order to plan and establish similar apical preparation sizes regardless of the study groups (Tables 1 and 2 ).

After chemomechanical preparation, the root canals were irrigated with 3 mL of 17% EDTA (Fórmula & Ação) for 3 min, followed by a final rinse with 5 mL of saline solution by using a NaviTip 31 G needle (Ultradent), inserted up to 5 mm from the AF, and dried with absorbent paper points (Dentsply-Maillefer).

For the root canal filling, the main gutta-percha cone corresponding to the master apical file was calibrated and stabilized at the AC and 1.5 mm from the AF for G1 and G3 and G2 and G4, respectively. This strategy was based on the greater possibility of gutta-percha extravasation to the periradicular tissues, considering the IFE had been carried out in teeth from G2 and G4.

After confirming the radiographic obturation limit, the main gutta-percha cone was coated with a zinc oxide-based sealer (Endofill, Dentsply Indústria e Comércio Ltda., Pirassununga, SP, Brazil), inserted into the root canal, and submitted to the thermocompaction process (Tagger's hybrid technique). After cleaning the pulp chamber, the following steps were conducted: i) provisional restoration of endodontic access with a temporary restorative material (Cavitec, Caitech, São José dos Pinhais, PR, Brazil); ii) occlusal adjustment (wholly taken out of occlusion); iii) final periapical radiography, and iv) referral of patients to perform definitive restoration. No medication was prescribed; however, the patients were instructed to take either 750 mg of paracetamol or 600 mg of ibuprofen every 6 h for three days in pain cases [ 28 ].

Analysis of postoperative pain

A dental assistant not involved in the treatment procedures contacted each patient by phone 24-, 48-, and 72 h post-treatment to assess their pain, which was classified according to a verbal rating scale (VRS) following a score (Table  3 ) [ 29 ]. The collected information was entered into a spreadsheet.

Statistical analysis

The Statistical Package for the Social Sciences Version 25.0 (SPSS Inc, Chicago, IL, United States of America) was used for the statistical analysis. The Kolmogorov–Smirnov test was applied to assess the normality of the data. Mann–Whitney U, Chi-square, Friedman's ANOVA, and Friedman's multiple 2 to 2 comparison tests were employed to identify potential significant statistical differences among the variables in the study groups ( P  < 0.05) [ 30 ].

Clinical and demographic data from the patients/teeth that constituted the sample of the current PRMCT and their respective statistical analyses are exposed in Table  4 . Significative statistical differences among the groups were only observed considering tooth, periradicular status, and the incidence of overfilling (sealer extrusion) ( P  < 0.00). Of 60 teeth of G3, 27 (45%) were first mandibular molars; meanwhile, in G1, G2, and G4, only 7 (11.7%), 8 (13.3%), and 5 (8.3%) first mandibular molars were present, respectively. Concerning periradicular status, in G1, 44 (73.3%) teeth showed AAP (with apical radiolucent areas). In G2, G3, and G4, 12 (20%), 40 (66.7%), and 27 (45%) teeth presented the same diagnosis in that order. Sealer extrusion (overfilling) happened in only 3 (5%) teeth from G1. In G2, G3, and G4, this event did occur in 24 (40%), 14 (23.3%), and 26 (43.3%) teeth, respectively.

All patients ( n  = 240) could be evaluated during the three time frames (24-, 48-, and 72 h). Considering the incidence and degree of postoperative pain, G1 presented the lower levels; however, this difference was just observed at 24 h ( P  < 0.05). No significant differences were observed among the groups at 48 and 72 h ( P ˃ 0.05) (Table  5 ).

It has been suggested that the physical trauma caused by using fine instruments to unblock the AF during chemomechanical preparation (apical patency) would not be enough to drive or increase postoperative pain [ 31 ]. On the other hand, the procedure cannot effectively provide the disinfection of the AF or in its vicinity [ 15 , 26 ], thus arousing a great interest of researchers about IFE. However, IFE may predispose to postoperative pain due to a virtually more significant apical extrusion of debris [ 20 ]. Since postoperative pain is a multifactorial event, this PRMCT was sought to investigate the levels and incidence of postoperative pain after single-visit root canal treatments performed in teeth affected by PN, and AAP (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas), comparing different instruments' kinematics (rotary or reciprocating) and apical instrumentation limits (with or without IFE). The null hypothesis was rejected because statistically significant differences were identified among the groups, whereas G1 presented lower pain levels 24 h after the treatments were concluded.

The study of the frequency and severity of postoperative pain after root canal treatment can be challenging due to the complexity of the matter [ 32 , 33 ], so thorough methodological planning is crucial. After establishing the variables and hypothesis to be investigated and the number of treated patients needed to provide reliable results after performing the current PRMCT, it was concluded that it would be essential to identify the profile of patients of professionals responsible for carrying out the treatments. These professionals unanimously stated that most patients referred by their indicators presented teeth previously submitted to the endodontic access. Therefore, adopting this inclusion criterion would drastically optimize the time required to complete the investigation. Furthermore, including specimens previously submitted or not to endodontic access would represent a significant methodological bias since the coronary opening itself represents an important step towards reducing the bacterial load present in the RCS due to the removal of the pulp tissue from the pulp chamber, which is normally widely infected and, therefore, could strongly influence in the occurrence and intensity of postoperative pain. Accordingly, only patients with teeth previously submitted to endodontic access constituted the sample. With the same objective of controlling the occurrence of biases, only symptom-free patients were included to ensure accurate results, as preoperative pain has been found to predict postoperative pain [ 34 ]. Therefore, previous research has reported that multiple- and single-visit root canal treatments have shown similar incidences and levels of postoperative pain [ 34 , 35 ] and healing of periapical tissues [ 36 ]. Nonetheless, in the present investigation, the treatments were carried out in a single session to reduce the number of clinical procedures and variables, such as intracanal dressing, which could compromise the analysis and reliability of the results [ 28 , 37 ].

Various methods have been used to mensurate pain following root canal treatment, such as visual analog scales (VAS) [ 28 , 38 ], (VRS) [ 39 , 40 ], or both [ 41 , 42 ]. Regardless of the method, it is essential to have an effective manner to ensure the patients can fully comprehend the questions and that the researchers can easily interpret the responses obtained [ 43 ]. A scoring system was used in this study to categorize the pain that patients experienced, based on a VRS, as follows: no pain, slight pain, moderate pain, and severe pain. The patients understood the categories, and this strategy is highly consolidated in the scientific literature [ 39 , 40 ].

Overall, the postoperative pain scores were low, with only one patient from G2 (1.7%) reporting acute/severe pain 72 h after the treatment. Machado et al. [ 26 ] observed similar results using the same instrumentation system used herein for G2 (Profile 04) to conduct large intentional foraminal enlargement (LIFE) during chemomechanical preparation. The same root canal filling protocol was carried out compared to the current research, and only one patient (1.66%) reported acute/severe pain 72 h after the treatment. No patient has reported severe pain after 72 h in G3 and G4. According to Cruz Junior et al. [ 28 ], to ensure thorough disinfection of the apical third while minimizing the risk of debris being extruded with a reciprocating system (Reciproc), it is essential to use plenty of irrigation and perform frequent recapitulation of the root canal preparation. The same care was established during the treatments performed in this research to avoid an equivalent adverse event. This and the following clinical and therapeutic strategies likely were the main ones responsible for the general low occurrence and intensity of postoperative pain observed in this PRMCT: i) only teeth with PN were included in the sample; ii) all teeth were submitted to occlusal adjustment at the end of the root canal treatment, and; iii) regarding the irrigation protocol, the amount of irrigating solution used was considerable, and the tip of the irrigation needle was inserted into the canal only to a safe depth (-5 mm from the AF) to prevent the extravasation of the irrigation solutions to the periapical tissues [ 39 ], and; iv) experienced operators were responsible by conducting the treatments [ 28 ].

Moderate pain was reported by 8, 4, and 3 patients and by 11, 7, and 4 patients after 24-, 48-, and 72 h for rotary (G1 and G2) and reciprocating (G3 and G4) groups, respectively. Therefore, there was a trend for decreasing postoperative pain over time. However, paired analyses showed a statistically significant difference only between 24 and 72 h for the groups submitted to the rotary (G1 and G2) and reciprocating (G3 and G4) kinematics. These findings are consistent with those obtained by a prospective, randomized, double-blinded clinical trial performed by Shokraneh et al. [ 44 ] and a systematic review and meta-analysis conducted by Pak and White [ 45 ].

Nonetheless, Yaylali et al. [ 37 ] noted increased pain in teeth that underwent IFE 48 h after the treatment. This conflicting outcome could be due to the variations in the methodological designs between the studies. In the study by Yaylali et al. [ 37 ], root canal treatment was only performed on molars with PN and AAP. Chemomechanical preparation was conducted using the ProTaper Next system (Dentsply-Maillefer) after establishing the working length (WL) at the AF or 1 mm short from this measurement. In addition, the irrigation protocol consisted of a 2.5% NaOCl solution using a Max-I-Probe needle up to 2 mm from the WL, and a VAS was used to address the prevalence and levels of postoperative pain. The authors did not mention the estimated size of the AF. In the present PRMCT, anterior and posterior teeth diagnosed with PN, and AAP (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas) were treated; nonetheless, before the chemomechanical preparation, anatomical diameters of the AF and AC were identified with the aim of planning and establishing similar apical preparation sizes regardless of the study group. Therefore, the chemomechanical preparation was conducted with 2.5% NaOCl employing a NaviTip needle inserted up to 5 mm short of the AF. Afterward, postoperative pain was assessed using a VRS.

Based on the methodological design established to carry out this investigation, there were no significant statistical differences considering the instrumentation’s kinematics evaluated. These findings contrast with the study performed by Nekoofar et al. [ 46 ], which showed a lower difference in postoperative pain levels between patients treated with a rotary system (ProTaper Universal) and those treated with a reciprocating system (WaveOne). This disparity might be explained by relevant methodological differences observed in the study by Nekoofar et al. [ 46 ] and the current PRMCT, respectively, such as the diagnosis (irreversible pulpitis versus PN), irrigating solution (chlorhexidine versus NaOCl), systems used during chemomechanical preparation (ProTaper Universal/WaveOne versus Profile 04/Reciproc), apical instrumentation limits (0.5 mm short from the AF versus 0.5 mm short or beyond this point), the use of intracanal dressing (with versus without), the sealer and filling technique (AH 26/lateral compaction versus Endofill/Tagger's hybrid technique), and the methods used for the analysis of the postoperative pain (numerical rating scale versus VRS).

About the limitations of the present study, although PRMCTs are placed at the top of the “hierarchical scientific pyramid” used to classify different types of research according to the scientific power based on their methodological planning and design, some of the features of PRMCTs may lead to biased results. In the current study, significant statistical differences among the groups were only observed considering tooth, periradicular status, and the incidence of overfilling (sealer extrusion). From 60 teeth comprising each group's sample, in G3, 27 (45%) were mandibular first molars. In G1, G2, and G4, only 7 (11.7%), 8 (13.3%), and 5 (8.3%) mandibular first molars were present, respectively. Therefore, considering the anatomical complexity that may have influenced these results is a reasonable hypothesis. Concerning periradicular status, in G1, 44 (73.3%) teeth showed AAP (with apical radiolucent areas). In G2, G3, and G4, 12 (20%), 40 (66.7%), and 27 (45%) teeth presented the same diagnosis in that order. Since the presence of a periapical lesion represents the chronicity of an inflammatory process, the more significant number of teeth with AAP (with apical radiolucent areas) in G1 may have contributed to the lower incidence and levels of postoperative pain observed in this group. Sealer extrusion (overfilling) happened in only 3 (5%) teeth from G1. In G2, G3, and G4, this event did occur in 24 (40%), 14 (23.3%), and 26 (43.3%) teeth, respectively. Considering that higher rates of postoperative pain have already been associated with the use and extravasation of zinc oxide and eugenol-based sealers [ 47 ], the lower incidence of this event in the teeth of G1 may also have contributed to the lower incidence and levels of postoperative observed in this group.

Still about the limitations of the current scientific investigation, someone could say that it did not only compare two but three parameters capable of influencing the postoperative pain after endodontic treatments performed in teeth with PN, and AAP (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas) (kinematics, apical limit, and number of files used during the chemomechanical preparation). Thus, the latter factor could also have influenced the results presented herein. However, some reflections based on the results of well-planned previous research are essential. Silva et al. [ 48 ] investigated the amount of apically extruded debris produced by two full rotary systems (ProTaper Universal and ProTaper Next) compared to two single file reciprocating systems (WaveOne and Reciproc) after large apical preparations by using sixty mandibular premolars with a single canal, randomly assigned into four groups (n. 15). The ProTaper Universal system was associated with significantly more debris than the others ( P  < 0.05). No significant differences were found between ProTaper Next, WaveOne, and Reciproc systems ( P  > 0.05). De-Deus et al. [ 49 ] conducted a study to evaluate the amount of dentin debris quantitatively extruded from the apical foramen by comparing the full sequence of the ProTaper Universal system with the single-file ProTaper F2 used in reciprocating kinematics. Thirty mesial roots of lower molars were selected, and different instrumentation techniques resulted in 3 groups (n. 10 each). In G1, a crown-down hand-file technique was used, and in G2, a full sequence of the ProTaper Universal system was used. In G3, the ProTaper F2 file was used in a reciprocating motion. The apical preparation was equivalent to a 25 ISO size file. No significant difference was found in the amount of debris extruded between the full sequence of the ProTaper Universal system and the single-file ProTaper (F2) used in reciprocating kinematics ( P  > 0.05). In contrast, the hand instrumentation group extruded significantly more debris than both NiTi groups ( P  < 0.05). A prospective, parallel, randomized clinical trial conducted by Saber et al. [ 50 ], aimed to assess the effect of instrumentation kinematics (reciprocation [Wave One Gold] or continuous rotation [One Shape]) on bacterial reduction, postoperative pain, and incidence of flare-ups after root canal treatment of single-rooted mandibular premolars with AAP. Sixty-six patients were included in the study and were randomly allocated into two groups (n. 33) according to the studied systems. Under complete asepsis, bacterial samples were taken before (S1) and after (S2) a standard cleaning and shaping protocol. The bacterial reduction was evaluated using the culture technique and quantitative real-time polymerase chain reaction (qPCR) analysis. Postoperative pain was assessed using a VAS after 24-, 48-, and 72 h following treatment, while flare-ups were recorded and analyzed as a dichotomic variable (yes/no). The comparison between culture and qPCR methods showed that qPCR analysis demonstrated significantly higher pre-instrumentation baseline bacterial count ( P  < 0.05). The percentage of bacterial reduction, detected by either method, significantly decreased after instrumentation using both rotation and reciprocation kinematics ( P  < 0.05). However, the difference between the Wave One Gold and One Shape files was statistically non-significant ( P  > 0.05). The intra-group comparisons showed a significant reduction in postoperative pain with time ( P  < 0.05) for both groups. However, the inter-group comparison demonstrated that the difference in postoperative pain after the use of both systems was statistically non-significant ( P  > 0.05). The same occurred with the incidence of flare-ups ( P  = 1).

There is common sense that associates the extrusion of debris with postoperative pain in necrotic teeth, and IFE could contribute to that. However, Machado et al. [ 51 ] conducted a systematic review and meta-analysis to assess whether IFE was responsible for extruding more debris from extracted human teeth with fully formed apexes. Following the recommendations of Preferred Reporting Items for Systematic Review and Meta-Analysis – PRISMA, electronic and manual searches were performed to identify studies that evaluated the extrusion of debris, comparing different apical limits of instrumentation (with/without IFE). The quality of the studies selected was evaluated, and statistical analysis was conducted. Just three papers could be used to perform the meta-analysis. The heterogeneity was high, and the general risk of bias was moderate. However, there was no statistically significant difference in the extrusion of debris in teeth either submitted or not submitted to IFE.

Despite the status quo established around the subject, a careful and critical analysis is needed to analyze the association between the extrusion of debris and postoperative pain in Endodontics. Different instruments, kinematics, materials, substances, techniques, and apical limits should be studied. However, following Elmsallati et al. [ 52 ], besides the quantity of debris, the type and virulence of bacteria bound to debris and the resistance of host tissue are essential factors to be considered in this context. Therefore, the understanding that postoperative pain after endodontic procedures is a complex and extrinsic multifactorial phenomenon must be considered in future studies.

According to the main findings of this PRMCT, postoperative pain was lower when the chemomechanical preparation was carried out using a rotary file system (Profile 04) inserted up to the AC. However, this finding was just statistically relevant at 24 h ( P  < 0.05). No significant differences were observed among the groups at 48 and 72 h.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

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The patients received information about postoperative care, clinical and radiographic exams, and alternative treatment options. All of them (or caregivers for those under 18) were given details about the study and treatment protocol, and informed consent was obtained.

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R.M: conceptualization; data curation; investigation; methodology; resources; software; validation; visualization; writing—original draft. G.M: data curation; investigation; methodology; resources; software. D.C: data curation; investigation; methodology; resources; software. A.P.B: writing—original draft. J.N: writing—writing—original draft. C.C.R.F: formal analysis; visualization; writing—review and editing. S.A.I: formal analysis; investigation; methodology; software; validation, visualization. L.F.R.G: formal analysis; visualization; writing—review and editing. R.R.A: formal analysis; visualization; writing—review and editing. D. S: formal analysis; visualization; writing—review and editing. U.X.S.N: formal analysis; project administration; supervision; validation; visualization; writing—review and editing.

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This PRMCT was approved by the Human Research Ethics Committee of the Paranaense University – UNIPAR, Francisco Beltrão, PR, Brazil (CAAE. 46774621.6.0000.0109) on 02/09/2021. It was registered at The Brazilian Registry of Clinical Trials – ReBEC (RBR-3r967t) on 01/06/2023, was performed according to the principles of the Helsinki Declaration [ 24 ] and is reported following the Consolidated Standards of Reporting Trials Statement [ 25 ].

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Machado, R., Moreira, G., Comparin, D. et al. Postoperative pain after single-visit root canal treatments in necrotic teeth comparing instruments’ kinematics and apical instrumentation limits – a prospective randomized multicenter clinical trial. BMC Oral Health 24 , 481 (2024). https://doi.org/10.1186/s12903-024-04225-6

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DOI : https://doi.org/10.1186/s12903-024-04225-6

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• Apical instrumentation limit
• Asymptomatic apical periodontitis
• Root canal treatment
• Instruments' kinematics
• Intentional foraminal enlargement
• Postoperative pain

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