Which design uses alternating baseline and intervention phases to demonstrate experimental control?

• A. AB design
• B. ABAB reversal design
• C. Multiple baseline design
• D. Non-concurrent design

Answer: (B)

Demonstrating experimental control comes from showing that the behavior changes in direct relation to the manipulation. The ABAB reversal design does this by alternating baseline and intervention phases and repeating the sequence. When the intervention is applied, the target behavior changes in a predictable way; when the intervention is removed, the behavior tends to revert toward baseline; and when the intervention is reintroduced, the change recurs. This repeated alternation provides replication within the same subject, strengthening the conclusion that the intervention is driving the change rather than time or other factors. Other designs either do not include a reversal (one baseline and one treatment phase) or rely on staggered introductions across different targets or settings without reversing conditions, which offers weaker evidence of causal control. Hence, alternating baseline and intervention phases to demonstrate control is best exemplified by the ABAB reversal design.