Which design uses reintroduction of the intervention to replicate treatment effects and strengthen experimental control?

• A. ABAB Design
• B. Reversal design
• C. A-B-A design
• D. Antecedent

Answer: (A)

Replicating treatment effects by reintroducing the intervention strengthens experimental control. In this design, you start with a baseline, apply the intervention, withdraw it to return to baseline, and then reapply the intervention. If the target behavior increases with the intervention and decreases when it’s withdrawn, and then increases again when the intervention is applied a second time, you have strong evidence that the intervention is driving the change rather than other factors. That repeated introduction and withdrawal of the treatment across phases is what clarifies the functional relation between the intervention and the behavior. The other options either omit the second reintroduction of the treatment or don’t use a true reversal sequence, and an antecedent-focused option isn’t a treatment-control design. This is the ABAB design.