Which type of study measures behavior at an individual level and includes baseline measurements?

The choice of a single-case design is especially pertinent when discussing individual behaviors and interventions. This methodology focuses on the detailed observation and measurement of an individual over time, allowing for a rich understanding of behavioral changes. By including baseline measurements, researchers can establish a starting point for comparison against subsequent observations or interventions, enabling them to evaluate the effects of specific treatments or changes on that individual’s behavior.

Single-case designs are frequently used in the fields of psychology and behavioral analysis, where the unique characteristics or responses of an individual are central to understanding treatment efficacy. This focus on an individual, complemented by the iterative measurement process, ensures that findings can be robust and tailored to the subject's particular context.

In contrast, longitudinal studies typically measure the same individuals over extended periods but may not focus on the detailed behavior of a single subject at the level of intervention analysis. Correlational studies primarily explore relationships between variables rather than direct measurement of behavior change in an individual, and case-control studies generally compare two different groups rather than extensively measuring individual behavior over time. Thus, single-case design is the most fitting choice for the question posed.