What does a single-case experimental design focus on?

A single-case experimental design focuses on a detailed examination of one individual or a small group. This approach allows researchers to systematically observe and analyze the effects of an intervention or treatment on that specific case, providing deep insights into individual variability and how specific interventions may affect behavior or outcomes.

The core element of this design is its emphasis on the unique characteristics and circumstances of the individual or group being studied, making it particularly valuable in clinical settings where understanding the nuances of a particular client's experience can lead to tailored interventions. By carefully observing changes over time, researchers can identify causal relationships that may not be evident in larger group studies, where individual differences can dilute the observed effects.

In contrast to this approach, other options emphasize features that are not central to single-case experimental designs, such as the necessity of large sample sizes, the exclusive use of qualitative data, or extensive longitudinal studies, which do not align with the intense focus and detail that characterize single-case research.