Print Page | Contact Us | Report Abuse | Sign In | Join
Research Glossary
Share |

The most common terms in O&P research.

With this glossary the American Academy of Orthotists & Prosthetists intends to provide a research glossary for the orthotics and prosthetics (O&P) profession as a public service. Terms are not necessarily specific to O&P and have been collected from various resources, which are indicated. Since terminology is context-sensitive, the Academy highly recommends visiting the highlighted links and other pertinent information as is provided by various public and scientific resources such as libraries, universities and clinical terminology resources.

For additional resources, please see the ISPO Orthotic and Prosthetic Definitions/Dictionary.


In science, engineering, industry and statistics, accuracy is the degree of conformity of a measured or calculated quantity to its actual, nominal, absolute, or some other reference, value. Precision characterizes the degree of mutual agreement or repeatability among a series of individual measurements, values, or results.
Resource: Wikipedia
Analysis of Variance
see: ANOVA
ANOVA - Analysis of Variance
In statistics, analysis of variance (ANOVA) is a collection of statistical models and their associated procedures which compare means by splitting the overall observed variance into different parts. The initial technique of the analysis of variance was pioneered by the statistician and geneticist Ronald Fisher in the 1920s and 1930s, and is sometimes known as Fisher's ANOVA or Fisher's analysis of variance.
Resource: Wikipedia
Applied Research
The investigation of some phenomena to discover whether its properties are appropriate to a particular need or want. In contrast, basic research investigates phenomena without reference to particular human needs and wants.
Resource: GLOSSARY
In mathematics, there are numerous methods for calculating the average or central tendency of a list of numbers. The most common method, and the one generally referred to simply as the average, is the arithmetic mean. Please see the table of mathematical symbols for explanations of the symbols used.
Resource: Wikipedia
Basic Research
Basic research is experimental and theoretical work undertaken to acquire new knowledge without looking for long-term benefits other than the advancement of knowledge.
Resource: Charles Sturt University
The extent to which a measurement, sampling, or analytic method systematically underestimates or overestimates the true value of an attribute. FOR EXAMPLE, words, sentence structure, attitudes, and mannerisms may unfairly influence a respondent's answer to a question. Bias in questionnaire data can stem from a variety of other factors, including choice of words, sentence structure, and the sequence of questions.
Resource: Bureau of Justice - Center for Program Evaluation
The practice of keeping the trial participants, care providers, data collectors, and sometimes those analyzing data unaware of which intervention is being administered to which participant. Blinding is intended to prevent bias on the part of study personnel. The most common application is double-blinding, in which participants, caregivers, and outcome assessors are blinded to intervention assignment. The term masking may be used instead of blinding.
Resource: RCT bank glossary
The determination, by measurement or comparison with a standard, of the correct value of each reading on a measuring instrument. The standard may be maintained by a national or international organization.
Resource: Wikipedia
Case series
A descriptive, observational study of the diagnosis, prognosis, treatment, and/or outcome of a subject group with the same (or similar aspects) of a condition.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Case study
A descriptive, observational study of the diagnosis, prognosis, treatment, and/or outcome of a single subject.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Case-controlled study
A retrospective, observational study in which a subject group with an existing condition is compared to a similar subject group that does not have that condition. Information on possible casual factors are obtained from subject histories and used to evaluate the relationships between those factors and the risk of developing the condition of interest.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Cause and Effect
A form of analysis that examines the causes and consequences of events and ideas.
Resource: Glossary of useful terms
CFR - Code of federal regulations
A compendium of rules issued by federal agencies on multiple topics.
Resource: U of R, Glossary of research-related terms
Random variation. Difference between the outcomes from a sample of the population and the true value obtained from looking at the outcomes from the entire population. Statistical methods are used to estimate the probability that chance alone accounts for the differences in outcomes.
Resource: Statistical significance
Chi square test
Any statistical hypothesis test in which the test statistic has a chi-square distribution when the null hypothesis is true, or any in which the probability distribution of the test statistic (assuming the null hypothesis is true) can be made to approximate a chi-square distribution as closely as desired by making the sample size large enough.
Resource: Wikipedia
Clinical Practice Guideline
A systematically developed statement designed to assist clinician and patient decisions about appropriate health care for specific clinical circumstances.
Resource: Glossary of EBM Terms
Clinical Research
Study of drug, biologic or device in human subjects with the intent to discover potential beneficial effects and/or determine its safety and efficacy. Also called clinical study and clinical investigation.
Resource: West Coast Clinical Trials
Clinical trial
A carefully designed investigation of the effects of a drug, medical treatment, or device on a group of subjects.
Resource: HIV Glossary
Cochrane Review
Cochrane Reviews are based on the best available information about healthcare interventions. They explore the evidence for and against the effectiveness and appropriateness of treatments (medications, surgery, education, etc) in specific circumstances
Resource: The Cochrane Collaboration
Cohort study
A prospective, observational study of subjects that may develop a specific condition. Subjects without the condition at baseline are classified based on exposure to factors that may influence occurrence of the condition. Incidence of the condition is assessed after an appropriate follow-up time (typically long-term). The incidence of the condition in the exposed and unexposed subjects is compared to identify factors that affect the risk of developing the condition.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Confidence Interval
A range of values that has a specified probability of containing the rate or trend. The 95% (p-value = .05) and 99% (p-value = .01) confidence intervals are the most commonly used.
Resource: Glossary of statistical terms
Confounding Variables / Confounders
One or more variables not under the control of the experimenter that vary systematically with the independent variable, decreasing the experimenter's ability to isolate cause and effect.
Resource: Statistics glossary
Construct Validity
A form of validity for an operational definition. If a test has "construct validity" then it measures what it says it measures, or rather there is evidence that it measures what it says it measures. There are various standard ways of trying to establish that a test has "construct validity." One standard way is triangulation.
Resource: Definition of postmodern terms
Content Validity
The extent to which the measurement incorporates the domain of the phenomenon under study. For example, a measurement of functional health status should embrace activities of daily living, occupational, family, and social functioning, and so on.
Resource: LAST, J.M. (ed.) (1988) "A Dictionary of Epidemiology", 2nd edn., Oxford Medical Publications, Oxford University Press, New York
Control or control group
The control group in a clinical trial is the group of subjects that does not receive the experimental treatment, but receives either the currently approved standard treatment for the disease or an inactive substance [also called placebo].
Resource: HIV glossary
Controlled before-and-after trial
A prospective experimental study in which one or more subjects are assigned to an intervention group. No control group is formed; instead subjects serve as their own control. Subjects are evaluated once before and once after one or more interventions. Outcome measures are assessed after an appropriate follow-up time and results are compared between the studied conditions.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Controlled trial
A prospective experimental study in which subjects are non-randomly assigned to either a control or intervention group. Outcome measures are assessed after an appropriate follow-up time and results are compared between the control and intervention groups.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Correlation coefficient
In probability theory and statistics, correlation, also called correlation coefficient, is a numeric measure of the strength of linear relationship between two random variables. A number of different coefficients are used for different situations. The best known is the Pearson product-moment correlation coefficient, which is found by dividing the covariance of the two variables by the product of their standard deviations. Despite its name it was first introduced by Francis Galton.
Resource: Wikipedia
Cross-sectional study
A descriptive, observational study in which one or more subject groups are evaluated at one point in time to describe the population(s) of interest, assess the prevalence of a condition of interest, or evaluate the correlations between possible risk factors and a condition of interest.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Crossover trials
A study where patients are given all of the medications (treatments) to be studied, or one medication (treatment) and a placebo in random order. Also known as a crossover study.
Resource: Wikipedia
Declaration of Helsinki
An international ethical code first issued in 1964 by the 18th World Medical Assembly in Helsinki, Finland. It constitutes acceptable research and the ethical responsibilities of investigators. It addresses the need for peer review (IRB review). It is interesting that the FDA will not accept foreign data unless the studies were conducted in compliance with the Declaration of Helsinki (21 CFR 312.20, 46 Fed Reg 8953).
Resource: U of R, Glossary of research-related terms
A variety of socio-demographic characteristics that can be identified and used to categorize groups with shared behaviors or traits including: age; gender; ethnicity; income; and education. dependent variable
Resource: PRM 447
Dependent variable
In experimental research, the dependent variable is the variable presumed within the research hypothesis to depend on (be caused by) another variable (the independent variable); it is sometimes referred to as the outcome variable.
Resource: Research Methods Glossary
Double masked (blind) , placebo controlled, cross over design, randomized clinical trial
Subjects are randomly assigned to either placebo or study treatment. Neither the investigator, nor the subject knows the treatment assignment. The treatments are then switched at the halfway point.
Resource: U of R, Glossary of research-related terms
Double masked or double blind design (or trial)
A study comparing two or more treatments where neither the investigator nor the subject knows who has received which treatment. This minimizes potential bias.
Resource: U of R, Glossary of research-related terms
Effect Size
The difference between two population means divided by the standard deviation of either population, assuming that both groups have the same standard deviation.
Resource: University of Nebraska-Lincoln, Survey Statistics and Psychometrics
Eligibility criteria
The clinical and demographic characteristics that define those participants eligible to be enrolled in the trial.
Resource: Consort - Reporting and Trials
Ethics committee
An independent group of medical and nonmedical people who verify the integrity of a study and ensure the safety, integrity, and human rights of the study participants
Resource: Duke Clinical Research Institute
Assessment against a standard. Evaluations can assess both the process (of establishing a programme to deliver an outcome) and outcomes (ultimate objectives)
Resource: The Canterbury District Health Board gateway
Evidence-based practice (EBP)
The conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence-based practice requires the integration of individual clinical expertise with the best available external clinical evidence from systematic research and our patient’s unique values and circumstances.
Resource: Glossary of EBM Terms
Exclusion criteria
Characteristics that would prevent someone from being eligible to participate in a research project, as defined in project’s protocol
Resource: Duke Clinical Research Institute
Experimental research
A research methodology used to establish cause-and-effect relationships between the independent and dependent variables by means of manipulation of variables, control and randomization. A true experiment involves the random allocation of participants to experimental and control groups, manipulation of the independent variable, and the introduction of a control group (for comparison purposes). Participants are assessed before and after the manipulation of the independent variable in order to assess its effect on the dependent variable (the outcome).
Resource: Research Methods Glossary
Experimental trial
Experimental or quasi-experimental trials are prospective research studies that include one or more subjects, a control or comparison condition, one or more interventions, and data collected at known times. In experimental and quasi-experimental trials, interventions are applied by the researchers. The number of subjects, random assignment of the subject(s) and control(s), and the frequency of data collection will identify a trial as a randomized control trial (E1), controlled trial (E2), interrupted time series trial (E3), single subject experimental trial (E4), or a controlled before-and-after trial (E5).
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Expert opinions
Expert opinions are peer-reviewed descriptive documents by acknowledged experts. The extent of agreement and synthesis of results will identify an expert opinion as a group consensus or an individual opinion.
External validity
The degree to which results of a study with a sample of subjects can be generalized to make statements about a much larger population of subjects.
Resource: Statistics glossary
Food and Drug Administration, Center for Devices and Radiological Health. In charge of regulations regarding medical devices (as Durable Medical Equipment (DME), orthoses and prostheses).
Resource: U.S. Food and Drug Administration
Frequency Tables
A frequency table is constructed by arranging collected data values in ascending order of magnitude with their corresponding frequencies.
Resource: Interactive Math - Second Edition
Group consensus
A peer-reviewed, descriptive synthesis of the results from a conference with multiple experts in a particular topic area. This may also include unstructured literature reviews that were not conducted with a comprehensive methodology consistent with a systematic review.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Health Insurance Portability and Accountability Act (HIPAA)
Legislation passed in 1996 that includes a privacy rule creating national standards to protect personal health information.
Resource: Duke Clinical Research Institute
Heterogeneity, heterogeneous
A heterogeneous compound, mixture, or other such object is one that consists of many different items, which are often not easily sorted or separated, though they are clearly distinct.
Resource: Wikipedia
HHS regulations
These are regulations to protect human subjects (in clinical research). Please see: 45 CFR Part 46, Protection of Human Subjects, which is available from the Office for Human Research Protections (OHRP), Department of Health and Human Services
Resource: Department of Health and Human Services
Historical control
Historical controls refer to data already available and compare them with subjects being treated currently
Resource: U of R, Glossary of research-related terms
Human subject
The FDA defines a "human subject" as an individual who is or becomes a participant in research, either as a recipient of the test article or as a control. A subject may either be a healthy human or a patient.
Resource: U of R, Glossary of research-related terms
A scientist's best estimation, based on scientific knowledge and assumptions, of the results of an experiment. It usually describes the anticipated relationship among variables in an experiment. The anticipated relationship between the dependent and independent variables is the result you expect when one variable reacts with another.
Resource: Lab Write Glossary
Inclusion criteria
A list of requirements that a person must meet to be eligible to participate in a research project, as specified in the protocol
Resource: Duke Clinical Research Institute
Independent Variables
A variable presumed to influence or precede another variable (dependent variable). The variable is systematically manipulated by the researcher to determine changes in the dependent variable. Also known as the experimental variable or moderating variable.
Resource: PRM 447
Individual opinion
A peer-reviewed descriptive document by one or more recognized experts in a particular topic area.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Inferential Statistics
Determines how likely a given result occurred by chance alone. Since we can rarely study an entire population, we study a sample of the population and by inference apply that result to the entire population.
Resource: Statistical significance
Informed Consent, Letter of Informed Consent
The process in which a patient learns about and understands the purpose and aspects of a clinical trial and then agrees to participate. Of course, a patient may decline to participate. This process includes a document defining how much a patient must know about the potential benefits and risks of therapy before being able to agree to undergo it knowledgeably. (Informed consent is required in federally conducted, funded or regulated studies a swell as by many state laws.) If a patient signs an informed consent form and enters a trial, he or she is still free to leave the trial at any time, and can receive other available medical care.
Internal Validity
The ability to show that the independent variable was responsible for the change in the dependent variable because the researcher was able to control all the variables.
Resource: Marketing essentials
Interobserver / Intertester reliability
The interobserver reliability of a survey instrument, like a psychological test, measures agreement between two or more subjects rating the same object, phenomenon, or concept.
Resource: Statistical glossary
Interrupted time series trial
A prospective experimental study in which multiple subjects are assigned only to an intervention group. No control group is formed; instead subjects serve as their own control. Subjects are evaluated multiple times before and multiple times after one or more interventions. Outcome measures are assessed at known pre/post intervals and results are compared between the studied conditions.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
A method of data collection involving an interviewer asking questions of another person (a respondent) either face-to-face or over the telephone.
Resource: Research Methods Glossary
Intraobserver / Intratester reliability
Intraobserver reliability indicates how stable responses are that are obtained from the same respondent at different time points. The greater the difference between the responses, the smaller the intraobserver reliability of the survey instrument.
Resource: Statistical glossary
IRB - Institutional Review Board
A committee of physicians, statisticians, researchers, community advocates, and others that ensures that a clinical trial is ethical and that the rights of study participants are protected. All clinical trials in the US must be approved by an IRB before they begin.
Resource: Mayo Clinic Clinical Trials Glossary
Letter of Informed Consent
See Informed consent
Level of significance
The probability of incorrectly rejecting the null hypothesis, i.e. saying that there is a difference between two groups when actually there is none. Otherwise known as the probability of Type I error. By convention, the level of significance is often set to a p value of 0.01 or 0.05.
Resource: Statistical significance
Literature review
An extensive search of the information available on a topic which results in a list of references to books, periodicals, and other materials on the topic.
Resource: Online Learning Center
Longitudinal Research
Longitudinal studies form a class of research methods that involve observations of the same items over a longer time. Many longitudinal studies are medically related. The alternative is a cross-sectional study.
Resource: Wikipedia
A mathematical average of a set of numbers or measurements, with the mean equaling the sum of the numbers divided by the number of units. The mean radius of the Moon, for example, is the average radius figured from multiple measurements.
Resource: Moonpedia
Measurement scale
Measurement of a phenomenon or property means assigning a number or category to represent it. The methods used to display and/or analyze numerical (quantitative) data will depend on the type of scale used to measure the variable(s). There are four scales of measurement: nominal, ordinal, interval, or ratio. The data associated with each measurement scale are referred to as nominal data, ordinal data, interval data and ratio data respectively.
Resource: Research Methods Glossary
The middle number or item in a set of numbers or objects arranged from least to greatest, or the mean of the two middle numbers when the set has two middle numbers.
Resource: MOESC Mathematics Course of Study
A statistical analysis that combines the results frommultiple studies. Meta-analyses adhere to a structured and appropriate procedure for identifying, including, and analyzing data found in a body of literature.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
The way in which information is found or something is done. The methodology includes the methods, procedures, and techniques used to collect and analyze information
Resource: EPA Evaluation Support
A descriptive statistic that is a measure of central tendency; it is the score/value that occurs most frequently in a distribution of scores.
Resource: Research Methods Glossary
Negative correlation
A relationship between two variables where higher values on one variable tend to be associated with lower values on the second variable; sometimes referred to as an inverse relationship (e.g. age of non-vintage cars and their market value).
Resource: Research Methods Glossary
NIH - National Institutes of Health
The steward of biomedical and behavioral research for the nation. Its mission is science in pursuit of fundamental knowledge about the nature and behavior of living systems and the application of that knowledge to extend healthy life and reduce the burdens of illness and disability.
Resource: National Institutes of Health
Nominal Scales
Nominal measurement consists of assigning items to groups or categories. No quantitative information is conveyed and no ordering of the items is implied. Nominal scales are therefore qualitative rather than quantitative. Religious preference, race, and sex are all examples of nominal scales.
Resource: Hyperstat online
Nonparametric Statistic
a statistic computed without knowledge of the form or the parameters of the distribution from which observations are drawn
Resource: Wordnet Princeton
Nonsignificant result
The result of a statistical test which indicates that the outcome of an experimental research study could have occurred through random variation (or chance) at a specified level of significance, rather than as a result of manipulation of the independent variable.
Resource: Research Methods Glossary
Normal Distribution
A term synonymous with the standard normal distribution. The normal distribution (a bell-shaped curve) represents a theoretical frequency distribution of measurements. In a normal distribution, scores are concentrated near the mean and decrease in frequency as the distance from the mean increases.
Resource: ASAP Definition of terms
Null Hypothesis
The proposal that no difference exists between groups or that there is no association between risk indicator and outcome variables. If the null hypothesis is true then the findings from the study are the result of chance or random factors. The overall purpose of a typical study is to "reject the null hypothesis." Another example: there is less than a 1 in 20 chance that the differences between treatments seen in this trial could have occurred by chance; less than a 1 in 20 chance that the null hypothesis is true.
Resource: Statistical significance
Observational studies
Observational studies include one or more subjects evaluated at a moment in or over a period of time. In observational studies, interventions are not applied by the researchers. Instead, outcomes and influencing factors are observed in order to draw correlations between them. The timing of the measurement(s), number of subjects, frequency of data collection, and type of data collected will identify an observational study as a cohort study, case-controlled study, cross-sectional study, qualitative method study, case series, or case study.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
A ratio of the number of people incurring an event to the number of people who don’t have an event.
Resource: Glossary of EBM Terms
Odds ratio (OR)
The ratio of the odds of having the target disorder in the experimental group relative to the odds in favor of having the target disorder in the control group (in cohort studies or systematic reviews) or the odds in favor of being exposed in subjects with the target disorder divided by the odds in favor of being exposed in control subjects (without the target disorder).
Resource: Glossary of EBM Terms
Open label trials
A clinical trial in which researchers and participants know which drug or vaccine is being administered
Ordinal Scales
An ordinal scale defines a total preorder of objects; the scale values themselves have a total order; names may be used like "bad", "medium", "good"; if numbers are used they are only relevant up to strictly monotonically increasing transformations
Resource: Wikipedia
Outcome measures
Data used to measure achievement of objectives and goal(s).
Resource: Juvenile Justice Evaluation Center
Indicates the probability that the result obtained in a statistical test is due to chance rather than a true relationship between measures. Small p-values indicate that it is very unlikely that the results were due to chance. Therefore, if the p-value is small, statisticians would be confident that the result obtained is "real."
Resource: APLA
The most commonly accepted definition of paradigm is that of Thomas Kuhn who describes a paradigm as the set of common beliefs and agreements shared between scientists about how problems should be understood and addressed [Kuhn, 1962].
Resource: Initial glossary
In mathematics, statistics and the mathematical sciences, parameters are quantities that define certain relatively constant characteristics of systems or functions. In some non-technical contexts or in jargon, parameter may simply be a synonym for criterion.
Resource: Wikipedia
Parametric Statistics
Can be carried out on data which is interval or ratio scale, and thus is suitable for arithmetic operations such as addition and subtraction. This enables parameters such as mean and standard deviation to be defined.
Resource: St. Andrews statistics glossary
Pearson Correlation coefficient
Measures the strength of the linear relationship between two variables.
Resource: Wink's statistics
Positive correlation
A relationship between two variables where higher values on one variable tend to be associated with higher values on the second variable (e.g. physical activity level and pulse rate).
Resource: Research Methods Glossary
Power Analysis or Statistical Power
The power of a statistical test is the probability that the test will reject a false null hypothesis (that it will not make a Type II error). As power increases, the chances of a Type II error decrease, and vice versa. The probability of a Type II error is referred to as ß. Therefore power is equal to 1 - ß.
Resource: Wikipedia
Principal investigator
An individual who conducts an investigation, ie, under whose immediate direction research is conducted, or, in the event of an investigation conducted by a team of individuals, is the responsible leader of that team.
Resource: Clemson University - Definitions of Research Compliance Terms
A measure of how likely it is that some event will occur; a number expressing the ratio of favorable cases to the whole number of cases possible; "the probability that an unbiased coin will fall with the head up is 0.5"
Resource: WordNet Princeton
Prospective study (Concurrent control)
A study designed to follow participants forward in time, rather than retrospectively.
Resource: AMFAR
Protected Health Information (PHI)
A subset of health information, including demographic information collected from an individual, and 1) is created or received by a health­care provider, health plan, employer, or health­care clearinghouse; and, 2) relates to the past, present, or future physical or mental health or condition of an individual, the provision of health care to an individual, or the past, present, or future payment for the provision of health care to an individual; and, that identifies the individual or where there is a reasonable basis to believe the information can be used to identify the individual [45 CFR § 164.501].
Resource: CDC
The formal design or plan of an experiment or research activity; specifically, the plan submitted to an IRB for review and to an agency for research support. The protocol includes a description of the research design or methodology to be employed, the eligibility requirements for prospective subjects and controls, the treatment regimen(s), and the proposed methods of analysis that will be performed on the collected data.
Resource: University of Virginia - SBS Glossary
Qualitative data
Information gathered in narrative (nonnumeric) form (e.g. a transcript of an unstructured interview).
Resource: Research Methods Glossary
Qualitative Research
Research involving detailed, verbal descriptions of characteristics, cases, and settings. Qualitative research typically uses observation, interviewing, and document review to collect data.
Resource: Bureau of Justice Assistance
Qualitative study
A descriptive, observational study in which a subject group is evaluated through subjective, open-ended questions and interview techniques
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Quality of life studies
A study looking at how your treatment or illness affects you is called a 'quality of life' study
Resource: Cancer research UK
Quantitative data - numerical data
Numerical data (or quantitative data) is data measured or identified on a numerical scale. Numerical data can be analysed using statistical methods, and results can be displayed using tables, charts, histograms, and graphs. For example, a researcher will ask a questions to a participant that include words how often, how many or percentage. The answers from the questions will be numerical.
Resource: Wikipedia
Quantitative Research
Research that examines phenomenon through the numerical representation of observations and statistical analysis.
Resource: Bureau of Justice Assistance
A method of assigning study treatment such that each participant has an equal chance of being assigned to each treatment or control group. Randomization guards against selection bias, that is, that specific criteria are used to assign patients to one group or another.
Resource: Duke Clinical Research Institute
Randomized control trial
A prospective experimental study in which subjects are randomly assigned to either a control or intervention group. Outcome measures are assessed after an appropriate follow-up time and results are compared between the control and intervention groups
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
A measure of variability indicating the difference between the highest and lowest values in a distribution of scores.
Resource: Research Methods Glossary
Ratio Scales
Variables measured at the ratio level are called ratio variables. Most physical quantities, such as mass, length or energy are measured on ratio scales so temperature is measured in Kelvins, that is, relative to absolute zero. The central tendency of a variable measured at the ratio level can be represented by its mode, its median, its arithmetic mean, or its geometric mean; as with an interval scale, however, the arithmetic mean gives the most useful information. Social variables of ratio measure include age, length of residence in a given place, number of organizations belonged to or number of church attendances in a particular time. Only ratio or interval scales can correctly be said to have units of measurement.
Resource: Wikipedia
Regression Analysis
Examines the relation of a dependent variable (response variable) to specified independent variables (predictors).
Resource: Wikipedia
The degree to which a source addresses a research topic (some relevant sources may be more broad or more narrow than the specific research topic.)
Resource: University Libraries Colorado
The probability of performing a specified function without failure under given conditions for a specified period of time.
Resource: Eurofix Glossary
The precision with which repeat measurements of the same sample give the same value with all conditions unchanged between measurements, except time.
Resource: Zygo Glossary of terms
Research Plan - Research Protocol
"Research plan" is a synonym for "research protocol". A research protocol consists of: Title of the research project Project summary Statement of the problem (scientific justification) Justification and use of the results (final objectives, applicability) Theoretical framework (argumentation, possible answers, hypothesis) Research objectives (general and specific) Methodology Type of study and general design Operational definitions (operationalization) Universe of study, sample selection and size, unit of analysis and observation. Selection and exclusion criteria Proposed intervention (if applicable) Data collection procedures, instruments used, and methods for data quality control Ethical considerations in research with human subjects Plan for analysis of results Methods and models of data analysis according to types of variables Programs to be used for data analysis Bibliographic references Timetable Budget Annexes
Resource: PAN Amarican Health Organization
Retrospective study
A study involving data that have already been collected (e.g. a chart review).
Resource: U of R, Glossary of research-related terms
A procedure used to choose subjects for research. Ideally, the participants chosen should be representative of the population being studied. (see Selecting Human Participants for Research) Example: If you are studying the behavior of gifted children, your sample should be drawn exclusively from this group.
Resource: Houghton Mifflin - College Division
Sampling bias
Distortion that occurs when a sample is not representative of the population from which it was drawn.
Resource: Research Methods Glossary
The measurement of a variable in such a way that it can be expressed on a continuum. Rating your preference for a product from 1 to 10 is an example of a scale.
Resource: Wikipedia
An operating characteristic of a diagnostic test that measures the ability of a test to detect a disease (or condition) when it is truly present. Sensitivity is the proportion of all diseased patients for whom there is a positive test, determined as: [true positives, (true positives + false negatives)].
Resource: INAHTA - Global Networking for Effective Healthcare
Side effects
A side effect is any effect other than an intended primary effect. It may or may not be expected, and it may be adverse or beneficial. It is a term often used in the following fields: In medicine, with regard to drugs or medical procedures; see adverse effect (medicine); In laws and regulations, to describe its unintended effects; In computing; see side effect (computer science).
Resource: Wikipedia
In statistics, a result is called significant if it is unlikely to have occurred by chance. "A statistically significant difference" simply means there is statistical evidence that there is a difference; it does not mean the difference is necessarily large, important or significant in the usual sense of the word.
Resource: Wikipedia
Single masked (blinded) design
The subject does not know the treatment assignment but the investigator does.
Resource: U of R, Glossary of research-related terms
Single subject experimental trial
A prospective experimental study in which one subject is given one or more interventions. The subject serves as his/her own control. The subject is evaluated multiple times before and after each intervention. Repeated outcome measures are assessed at known intervals and results are compared between the studied conditions
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
Standard deviation
A measure of variability. The standard deviation quantifies how much the values vary from each other. A measure of the spread of individual observations around the mean value of the sample. A normal, unskewed curve will have 34% of the cases between the mean and one standard deviation above or below the mean; 68% of cases between one standard deviation above and one below the mean; 95.5% of cases will be within two standard deviations of the mean.
Resource: Statistical significance
An estimate of a parameter calculated from a set of data gathered from a sample.
Resource: Research Methods Glossary
Statistical inference
A procedure using the laws of probability to infer the attributes of a population based on information gathered from a sample.
Resource: Research Methods Glossary
Statistical test
A statistical procedure that allows a researcher to determine the probability that the results obtained from a sample reflect true parameters of the underlying population.
Resource: Research Methods Glossary
Structured review
Structured reviews are the methodological collection, analysis, and presentation of information from multiple sources. The analysis of the collected information may be statistical or descriptive in nature, which will identify the structured review as a meta-analysis or a systematic review.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
A term most often used in positivist research to describe those who participate in research and provide the data.
Resource: Research Methods Glossary
Data collection techniques designed to collect standard information from a large number of subjects. Surveys may include polls, mailed questionnaires, telephone interviews, or face-to-face interviews.
Resource: BJA - Bureau of Justice Assistance
Systematic review
A comprehensive methodological review and critical appraisal of literature obtained from multiple sources. Systematic reviews adhere to a structured and appropriate procedure for gathering, selecting, evaluating and reporting the evidence found in a body of literature.
Resource: The American Academy of Orthotists and Prosthetists (AAOP), State-of-the-Science Evidence Report Guidelines
A statistical significance test used to compare differences between means.
Resource: Google definition
Tabulations - cross tabulations
A cross tabulation (often abbreviated as cross tab) displays the joint distribution of two or more variables. They are usually presented as a contingency table in a matrix format.
Resource: Wikipedia
Target Population
In statistical terminology the target population (often shortened to "population") may, but does not necessarily, refer to a population of people. It could be a population of schools, area units of farm land, freshwater lakes, or the network of streams. The description of the target population must explicitly identify the resource of interest and include criteria for determining whether a resource unit is in or out of the target population. 
Resource: U.S. EPA
In its most general sense a theory describes or explains something. Often it is the answer to 'what', 'when', 'how', or 'why' questions.
Resource: Research Methods Glossary
In research terms, validity refers to the accuracy and truth of the data and findings that are produced. It refers to the concepts that are being investigated; the people or objects that are being studied; the methods by which data are collected; and the findings that are produced. There are several different types of validity.
Resource: Research Methods Glossary
Something that takes on different values that can be measured or counted. If one variable can be controlled exactly (such as the selling price of apples) then it is called an 'independent variable', while the remaining variable (in this case the number of apples bought) is called a 'dependent variable'
Resource: NOVA - Science in the News
In probability theory and statistics, the variance of a random variable is a measure of its statistical dispersion, indicating how far from the expected value its values typically are.
Resource: Wikipedia

At the time of original posting all terminology links were active. Links may move or become inactive. If you should find a link that does not work, please email and put the problematic term in the subject line.


American Academy of Orthotists and Prosthetists
7910 Woodmont Avenue, Suite 760
Bethesda, MD 20814

(202) 380-3663