Practice question
Experimental Design

Identify threats to internal validity in weak designs.

Original BCBA scenario practice question with answer explanation and wrong-choice notes.

Question

Difficulty: easy. Skill: recognize. Type: experimental design critique.

throwing materials decreases after an intervention in a simple AB design, but a new staff routine in the group instruction period also began that same week. What is the main concern? The case is being discussed after two weeks of stable attendance.

A
A confounding variable limits confidence that the intervention caused the change

Correct answer

B
The aide proves the intervention was unnecessary
C
The decrease should be ignored because all AB designs are invalid
D
Internal validity is unrelated to treatment evaluation

Explanation

Answer A

A concurrent change can threaten internal validity because it competes with the intervention as an explanation for behavior change.

Why the other choices are weaker

B
Choice B

The aide is a possible confound, not proof of the true cause.

C
Choice C

AB data can be useful clinically, but causal confidence is limited.

D
Choice D

Internal validity concerns whether the intervention caused the observed change.

Study tags

Internal ValidityExperimental ControlInternal Validity

Practice interactively

Try more BCBA scenario questions in the interactive practice mode, then use review tools to track missed domains and flagged items.

Start practiceMore free questions