BCBA Experimental Design Practice Questions
Experimental Design questions ask you to identify a single-case design from a description, judge whether it demonstrates experimental control, and recognize threats to internal validity.
What Domain D covers
The 6th Edition Test Content Outline lists 9 tasks in this domain. Baseline has practice questions mapped to every one of them.
- D.1Dependent vs. independent variables
- D.2Internal vs. external validity
- D.3Threats to internal validity
- D.4Defining features of single-case designs
- D.5Single-case vs. group designs
- D.6Critiquing and interpreting single-case data
- D.7Reversal, multiple-baseline, multielement, and changing-criterion designs
- D.8Comparative, component, and parametric analyses
- D.9Applying single-case designs
What to master
- Independent vs. dependent variables, and internal vs. external validity.
- The logic of prediction, verification, and replication in single-case designs.
- Reversal, multiple-baseline, multielement (alternating treatments), and changing-criterion designs — when each is appropriate.
- Component, parametric, and comparative analyses.
Common traps
- Choosing a reversal design when withdrawing treatment would be unsafe or the behavior won't reverse.
- Forgetting that a multiple baseline requires functionally independent behaviors, settings, or participants.
- Calling an A-B design an experiment — it can't demonstrate a functional relation.
Free Experimental Design practice questions
Try these original questions written to match the format of the BCBA exam.
1. A behavior analyst wants to compare the effects of two different prompting procedures on a learner's skill acquisition, rapidly alternating the procedures across sessions in random order. Which design is this?
- Reversal (A-B-A-B) design
- Changing criterion design
- Multiple probe design
- Alternating treatments design
Show answer and explanation
Answer: D. Alternating treatments design
An alternating treatments (multielement) design rapidly alternates two or more conditions and compares the resulting data paths. It requires no withdrawal phase and can show differences quickly.
2. Withdrawing an effective treatment for a client's self-injury would be unethical. The behavior analyst wants to demonstrate experimental control by introducing the treatment at home, then at school, then in the community, at different points in time. Which design fits best?
- Alternating treatments design
- Multiple baseline across settings
- Reversal design
- A-B design
Show answer and explanation
Answer: B. Multiple baseline across settings
A multiple baseline across settings staggers the introduction of the intervention, showing that behavior changes only when — and where — treatment begins. It avoids a reversal. A simple A-B design cannot demonstrate experimental control.
Practice all 45 Experimental Design questions
Full Prep includes every question in this domain with explanations, smart practice that targets your weakest tasks, unlimited timed mock exams, and an AI tutor. Start with the free diagnostic to see where you stand.