ABA Exam Coach

G.13: Design and evaluate trial-based and free-operant procedures.

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

A BCBA wants to increase how often a child makes spontaneous requests for items during free play, without the therapist presenting instructions. Which approach and measure fit best?
  1. A. Discrete-trial training measured by latency to respond after the SD
    Latency after an SD assumes a trainer-presented instruction, which goes against the goal of spontaneity.
  2. B. A free-operant arrangement (for example, incidental teaching) measured by rate of mands per minute
    Correct. In free-operant arrangements, the learner can respond at any time, so rate is the right measure for spontaneous requests.
  3. C. Massed trials measured by trials to criterion
    Massed trials are still trainer-controlled and do not measure spontaneous initiation.
  4. D. Discrete-trial training measured by percent correct across 10 trials
    In DTT the trainer controls when opportunities occur, so it does not target spontaneous requesting.
In a discrete-trial program for receptive identification, the therapist presents an instruction, waits for a response, delivers a consequence, and pauses briefly before the next trial. Which dimension is most appropriate for summarizing performance?
  1. A. Percentage of trials with a correct response
    Correct. Discrete trials produce restricted-operant responding, which is usually summarized as percent correct or trials to criterion.
  2. B. Celeration
    Celeration describes change in rate over time and is better suited to free-operant data.
  3. C. Interresponse time
    IRT describes time between free-operant responses. It is not used for trial-by-trial accuracy.
  4. D. Rate of responding per minute
    Trial-based responding is limited by how often the trainer presents trials, so rate is less meaningful here.
A vocational trainer sets up a station where an adult can sort recyclables continuously for 20 minutes. Praise is given after every 5 items sorted, and the trainer gives no instructions between items. A colleague asks why this is a free-operant arrangement rather than a trial-based one. Which answer is most accurate?
  1. A. Reinforcement is given after every response the learner makes
    Reinforcement here is on a ratio schedule (every 5 items), not after every response. In any case, the reinforcement schedule does not decide whether a procedure is free-operant.
  2. B. Each response is preceded by a discrete instruction and followed by a pause
    A discrete instruction followed by a pause describes a trial-based (discrete-trial) procedure, not a free-operant one.
  3. C. The learner can respond at any time without waiting for a trainer-presented opportunity
    Correct. In free-operant arrangements, the learner can respond at any time and as often as they want, with no trainer-delivered cue before each response. Rate is limited only by the learner's own behavior.
  4. D. The trainer controls the number of opportunities to respond
    When the trainer controls the number of opportunities, the procedure is trial-based. In this setup, the learner controls how many responses occur.

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