Term in a research study for all people who enter a study regardless of treatment, exposure, or ability to complete the study?

• A. Study population
• B. Sample
• C. Cohort
• D. Control group

Answer: (A)

In study design, the term for everyone who enters a study, regardless of what treatment they receive or whether they complete the study, is the study population. This group includes all eligible individuals who enter and is the set from which data could be drawn and results generalized. A sample, by contrast, is just a subset used for analysis. A cohort refers to a group followed over time, often defined by shared characteristics, but not necessarily all entrants. A control group is the subset that does not receive the intervention, used for comparison. The study population is the best answer here because it specifically denotes all entrants into the study.