Which design emphasizes detailed analysis of the behavior of a single subject or a small number of subjects over time?

• A. Single-subject research
• B. Case-control study
• C. Cohort study
• D. Survey Research

Answer: (A)

Single-subject research emphasizes detailed, time-series analysis of behavior for one person (or a very small number) across different phases of an intervention. By repeatedly measuring the same subject, you can observe how behavior changes in direct relation to the treatment, with the subject serving as their own control. This setup lets you track the exact trajectory of change, variability, and stability over time and to demonstrate a causal link between the intervention and the observed behavior.

This is different from case-control studies, which compare groups with and without an outcome—often retrospectively and not focused on a single subject’s time-course. Cohort studies follow a larger group over time to observe incidence and progression, not the detailed within-subject pattern of change. Survey research collects data from many people to describe characteristics or opinions at one or more points, rather than repeatedly tracking behavior of a single subject.