BCBA domain D · 7% of the exam

Experimental Design

Variables, validity, and the single-case designs that show whether an intervention, not chance, changed behavior. A study guide for each of the 9 topics, about 71 minutes of reading.

Start with D.1 Try 8 free questions

scored exam questions: 13
of the BCBA exam: 7%
topics to know: 9
practice questions: 72

Topics in this domain

In outline order. Each guide ends with a quick check and a link to practice.

D.1Independent vs. dependent variablesTell the independent variable (what you change) from the dependent variable (the behavior you measure), and see how both support a functional relation.7 min read8 practice questions
D.2Internal vs. external validityInternal validity asks whether the intervention caused the change; external validity asks how far it reaches. Learn both, replication, and exam traps.8 min read8 practice questions
D.3Threats to internal validity, such as history and maturationSpot rival explanations, from history and maturation to observer drift and regression, that can mimic a treatment effect, and how designs rule them out.8 min read8 practice questions
D.4What makes a design single-case: repeated measures, prediction, verification, replicationHow single-case designs show control: repeated measurement, each person as their own control, and the prediction, verification, replication logic.8 min read8 practice questions
D.5Single-case vs. group designs: relative strengthsCompare single-case and group designs: what each shows well, what each hides, and how to match the design to the question being asked.7 min read8 practice questions
D.6Critiquing and interpreting single-case dataUse level, trend, variability, immediacy, and overlap to judge whether a single-case graph really shows that the intervention changed behavior.8 min read8 practice questions
D.7Reversal, multiple-baseline, multielement, and changing-criterion designsHow the four core single-case designs show experimental control, when to pick each one, and the limitations that decide which one fits.9 min read8 practice questions
D.8Why run comparative, component, and parametric analysesThree follow-up questions after an intervention works: which treatment is better, which parts are needed, and how much of the variable to use.8 min read8 practice questions
D.9Putting single-case designs to workChoose and run the right single-case design for a real client: reversibility, safety, number of targets, comparing treatments, and gradual change.8 min read8 practice questions

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