What does an ABAB reversal design demonstrate?

• A. ABAB reversal design demonstrates the effect of the intervention by comparing behavior across phases
• B. A simple AB design without reversal
• C. A multiple baseline design across participants
• D. A changing-criterion design

Answer: (A)

This design tests whether the intervention actually causes changes in the target behavior by comparing behavior across different phases. It alternates baseline and treatment: start with a baseline, apply the treatment, withdraw the treatment back to baseline, and then reapply the treatment. If the behavior systematically changes when the treatment is introduced and then withdrawn—and changes again when reintroduced—that pattern provides strong evidence that the intervention is driving the behavior, not other factors. The repeated reversals (replications) strengthen confidence in a functional relation between the treatment and the observed behavior. This is what sets it apart from a simple AB design, which lacks the withdrawal and reintroduction necessary to demonstrate causality. The other designs mentioned involve different structures: a multiple-baseline design across participants examines effects across different individuals without reversals, and a changing-criterion design looks at gradual changes toward a criterion rather than reversals.