In an A-B-A design, what does the last A indicate?

In an A-B-A design, the last A represents the return to the baseline condition after the treatment (B) has been implemented. This design is commonly used in single-subject research to observe the effects of an intervention. The structure of A-B-A allows researchers to assess the impact of the treatment by comparing behaviors during the baseline phase (A) both before and after the treatment phase (B).

The final A signifies that the intervention has been removed, allowing for an evaluation of whether the changes observed during the treatment phase persist or revert to baseline levels once the treatment ends. This is crucial for understanding the effectiveness of the treatment and maintaining control over external variables that may influence the results. The A-B-A design effectively demonstrates the relationship between the intervention and its outcomes by comparing behaviors across these different phases.