ABA Exam Coach

D.1: Distinguish between dependent and independent variables.

Free practice questions for this part of the BCBA, with an explanation for every option.

A BCBA wants to find out whether delivering adult attention on a fixed-time 2-minute schedule reduces the number of head hits per session for a 7-year-old client. In this evaluation, what is the independent variable?
  1. A. The client's age and diagnosis
    Incorrect. Client characteristics are not manipulated in this study; at most they are subject variables that describe the participant.
  2. B. The number of head hits per session
    Incorrect. Head hits per session is the measured behavior, which makes it the dependent variable.
  3. C. The clinic room where sessions occur
    Incorrect. The room is a setting variable the analyst should hold constant, not the variable being manipulated.
  4. D. The fixed-time 2-minute attention schedule
    Correct. The attention schedule is the condition the analyst deliberately manipulates to see whether behavior changes, so it is the independent variable.
A teacher gives a student token boards that require 3, 6, or 9 tokens before exchange, varying the board across sessions. For each session she records how many seconds pass between the work instruction and the student starting the first task. What is the dependent variable?
  1. A. The backup reinforcer the student picks at exchange
    Incorrect. The backup reinforcer is part of the procedure and is not the outcome being measured.
  2. B. Latency from the instruction to starting the first task
    Correct. Latency is the behavioral measure that may change as a result of the manipulation, which makes it the dependent variable.
  3. C. The number of tokens required on the board
    Incorrect. The token requirement is what the teacher varies on purpose, so it is the independent variable.
  4. D. The order in which the token boards are presented
    Incorrect. Presentation order is a design feature, controlled through counterbalancing; it is not the measured outcome.
A warehouse supervisor wants fewer order-picking errors. She starts posting a daily chart in the break room that shows each team's picking accuracy. A BCBA records the number of picking errors per 100 orders before and after the chart is introduced. What is the independent variable?
  1. A. The daily feedback chart posted in the break room
    Correct. The independent variable is the environmental change the analyst deliberately introduces to see whether it changes behavior. Here, that is the posted feedback chart.
  2. B. The number of picking errors per 100 orders
    This is the dependent variable. It is the measure of behavior that is expected to change.
  3. C. The warehouse employees who pick the orders
    The employees are the participants whose behavior is measured. They are not a variable that is manipulated.
  4. D. The shift on which the error data are collected
    The shift is a measurement detail or a possible extraneous variable. It is not the intervention being evaluated.

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