PRF key terms

A precise, answerable statement identifying the population, variables or phenomena, and outcome of interest that directs every later decision about design, sampling, and analysis.

A written plan fixed before data collection that specifies objectives, design, eligibility, sampling, measures, analysis, and governance, allowing reviewers to judge whether procedures were followed as intended.

An organized set of assumptions and constructs that explains how the investigator believes variables or phenomena relate, guiding which measures are chosen and which relationships are tested.

The single prespecified measure that answers the main research question and on which the sample size calculation is based, protecting against selective emphasis on favorable results.

The probability that a study will detect a real effect of a stated size, conventionally set at 0.80 or higher, determined by effect size, variability, alpha, and sample size.

A voluntary agreement to participate given after a person receives and understands information about purpose, procedures, risks, benefits, alternatives, and the right to withdraw without penalty.

An independent committee that reviews research involving humans or animals before it begins, judging risks, benefits, consent procedures, and protections for vulnerable groups.

Agreement to take part given by a person who lacks legal capacity to consent, such as a child, paired with permission from a parent or legally authorized representative.

A group whose circumstances, such as imprisonment, cognitive impairment, poverty, or dependent status, raise the risk of coercion or harm and therefore require extra safeguards.

Fabrication, falsification, or plagiarism in proposing, performing, or reporting research, distinct from honest error and from disputes about authorship or interpretation.

Presenting another person's words, ideas, data, or images as one's own without adequate attribution, including close paraphrase and unattributed reuse of one's own prior work.

Inventing data, participants, or results that were never actually collected or observed, a serious breach of integrity that invalidates any conclusion drawn from the record.

A financial or personal interest that could reasonably be seen to bias professional judgment about a study's design, conduct, or reporting, disclosed so readers can weigh it.

Public recording of a study's design and outcomes in a recognized registry before enrollment, enabling comparison between what was planned and what was reported.

A review that answers a focused question by using explicit, reproducible methods to locate, screen, appraise, and synthesize all eligible studies, often with meta-analysis.

A statistical technique that pools effect estimates from multiple studies into a weighted summary estimate, quantifying consistency through measures such as heterogeneity.

The tendency for studies with significant or favorable results to be published, submitted, or cited more readily, distorting summaries built only from the available literature.

A scatterplot of study effect size against a precision measure, used to inspect asymmetry that may suggest missing small studies with null or unfavorable findings.

Structured judgment of a study's validity, results, and applicability, examining selection, measurement, confounding, and analysis to decide how much weight its findings deserve.

A ranking of study designs and evidence bodies by their capacity to support causal or clinical conclusions, typically placing systematic reviews of trials above single observational studies.

A statement translating an abstract construct into concrete, observable procedures or scores, specifying exactly what is measured, how, and by which instrument.

The consistency of measurements across repeated occasions, raters, or items, commonly quantified with coefficients of internal consistency, test-retest, or inter-rater agreement.

The degree to which an instrument measures what it is intended to measure and supports the interpretations and decisions made from its scores in a given context.

Evidence that scores behave as the underlying theoretical concept should, shown through relationships with related measures, distinctness from unrelated ones, and sensitivity to expected change.

The extent to which different observers assign the same scores or categories to the same material, often summarized by kappa or intraclass correlation coefficients.

The difference between an observed value and the true value, arising from instrument imprecision, observer variation, or fluctuating conditions, which attenuates or distorts observed relationships.

The chance difference between a sample statistic and the population parameter it estimates, which shrinks as sample size grows and is reflected in confidence intervals.

Selection of participants by a random mechanism giving every eligible unit a known chance of inclusion, supporting generalization and unbiased estimation of population parameters.

Recruitment of participants who are easiest to reach, which is practical and common in qualitative and pilot work but limits claims about representativeness and generalization.

Distortion of an exposure-outcome relationship by a third variable associated with both, which can create, inflate, or mask an association unless addressed in design or analysis.

Allocation of participants to conditions by chance, which balances known and unknown confounders on average and supports causal interpretation of between-group differences.

An experiment in which participants are randomly assigned to an intervention or comparison condition and followed prospectively, providing the strongest single-study evidence for efficacy.

Analysis that includes every randomized participant in the group originally assigned, regardless of adherence, preserving the benefits of randomization and giving conservative effectiveness estimates.

A standardized quantity describing the magnitude of a difference or association, such as a mean difference or correlation, independent of sample size and central to power planning.

A range of plausible values for a population parameter, calculated so that a stated percentage of such intervals would contain the true value across repeated sampling.

The likelihood that a study's design, conduct, or analysis produced a result deviating systematically from the truth, assessed domain by domain in appraisal tools.

Distortion introduced when participants who leave a study differ systematically from those who remain, especially when dropout is unequal across comparison groups.

Selective reporting of some measured outcomes or analyses while omitting others, typically favoring statistically significant or expected findings over null results.

Deliberate selection of information-rich cases that meet criteria relevant to the research question, common in qualitative work where statistical representativeness is not the aim.

The point at which additional data collection yields no new codes, themes, or insights, used to justify ending sampling in qualitative studies.

Use of multiple data sources, methods, investigators, or theories to examine the same phenomenon, strengthening confidence when findings converge and revealing discrepancies worth explaining.

A design that combines qualitative and quantitative data within one study, integrating them through explicit procedures such as convergent, explanatory sequential, or exploratory sequential structures.

A document describing how data will be named, stored, backed up, access-controlled, documented, shared, and eventually destroyed, written before collection begins.

Descriptive information about data, such as variable labels, units, collection dates, and coding decisions, that makes a dataset intelligible and reusable by others.

Irreversible removal or transformation of identifying information so that individuals cannot reasonably be re-identified, stronger protection than pseudonymization or simple de-identification.

The ability of another researcher to obtain the same results using the same data and analysis code, supported by shared materials, documented steps, and version control.

Public posting of hypotheses, design, and analysis plans before data are examined, distinguishing confirmatory tests from exploratory analyses conducted after seeing results.

A reporting guideline for systematic reviews that specifies items for search strategy, study selection, risk of bias, synthesis, and a flow diagram of records screened and included.

A checklist of items that a study report should include so readers can judge methods and replicate work, with versions tailored to designs such as trials, observational studies, or qualitative research.

A publication that charges fees while providing little or no peer review or editorial oversight, often soliciting submissions aggressively and misrepresenting its indexing and impact.

The process of moving research findings into practice, policy, or public understanding through tailored messages, stakeholder engagement, and attention to local context and barriers.