In single subject research design, how many subjects are typically evaluated?

In single-subject research design, the focus is primarily on the individual rather than a larger population. This methodology is predicated on the intensive study of one or a small number of subjects to observe and analyze behavior changes over time in response to an intervention. This allows for a detailed examination of the effects of a treatment or strategy on the unique behaviors of the subject(s), thereby providing valuable insights into individual variability and progress.

Additionally, with a small number of subjects, researchers can implement repeated measures and closely monitor the effects of the intervention, which is central to this research design. This approach often makes use of baseline and intervention phases, enabling the analysis of individual responses to various conditions.

In contrast to the correct option, studying many subjects simultaneously or focusing on groups of average individuals does not align with the singular focus of a single-subject design, which aims for depth over breadth in understanding individual responses. There is also no fixed requirement for the number of subjects, but the essence of single-subject design is its concentrated examination of a few individuals rather than generalization across larger groups.