Experimental Design
Single-case design selection
Select a design based on reversibility, safety, behavior-change trajectory, and the need for replication.
How this shows up in scenario questions
- 1Use multiple baseline when reversal is unsafe or impractical.
- 2Use changing criterion for gradual performance goals.
- 3Use alternating treatments for rapid treatment comparison.
Common misconceptions
- Using reversal for irreversible skills.
- Calling an AB design strong experimental control.
- Choosing design based only on graph appearance.
Distractor patterns
- AB design with no replication.
- Reversal that withdraws a safety skill.
- Scatterplot as experimental design.
Related terms
reversal designmultiple baselinechanging criterionalternating treatments
Related practice prompts
Select a multiple-baseline design when reversal is unsafe or impractical.
A BCBA wants to evaluate a handwashing intervention across three school routines. Withdrawing the intervention after improvement would be inappropriate for health reasons. Which design is most suitable?
Select a multiple-baseline design when reversal is inappropriate.
A BCBA evaluates teaching following a schedule across three routines in a elementary classroom. Withdrawing the skill after mastery would be impractical and potentially unsafe. Which design best fits? The BCBA is reviewing the decision with a trainee.
Identify threats to internal validity in weak designs.
repeating questions decreases after an intervention in a simple AB design, but a new staff routine in the early-intervention session also began that same week. What is the main concern? The program is being updated before services move to a new setting.