Constant: a fixed value. Not a variable.
Variable: a value or characteristic that differs among individuals. It can be described, counted, or measured.
Independent Variable: the variable researchers manipulate in an experiment. Affects the dependent variable(s).
Dependent Variable: the variable affected by the independent variable in an experiment.
More information on different types of variables and sampling can be found here.
Sample: a smaller group selected from a larger group (the population). Researchers study samples to draw conclusions about the larger group.
Population: the entire collection of people, animals, plants, things, etc. researchers wish to examine. Since populations are often too large to include every member in a study, researchers work with samples to describe or draw conclusions about the entire population group using statistical tests.
Participant: an individual who participates in a study. This is a more recent term. (Used with human research.)
Subject: another way to describe a participant. This is a more traditional term. (Used with human and animal research.)
Attrition: loss of participants/subjects in a study.
Generalizability: The goal of research is to produce knowledge that can be applied as widely as possible. Researchers must ensure that the sample accurately resembles the broader population in order to claim the results are generalizable (or applicable to other groups and situations). Generalizability is one of the three criteria (with validity and reliability) that researchers use to assess the quality of quantitative and qualitative research. However, depending on the type of research, generalizability is interpreted and evaluated differently. (Source: Nikolopoulou 2023).
Reliability: the extent to which a measure or tool yields consistent results on repeated trials.
Validity: the degree to which a study accurately assesses what it is attempting to assess.
More on reliability and validity can be found here.
References
Nikolopoulou, K. (2023, March 03). What Is Generalizability? | Definition & Examples. Scribbr. Retrieved February 10, 2025, from https://www.scribbr.com/research-bias/generalizability/
