Chapter 12

• AB design

  • A design in which a baseline condition (A) is measured first, followed by measurements during the experimental intervention (B).
  • There is no return to the baseline condition.
• ABA design

  • A design in which a baseline condition (A) is measured first, followed by measurements during the experimental condition (B), followed by a return to the baseline condition (A) to verify that the change in behavior is linked to the experimental condition.
  • Also called a reversal design.
• ABAB design


  A design in which a baseline condition (A) is measured first, followed by measurements during a treatment condition (B), followed by a return to the baseline condition (A) to verify that the change in behavior is linked to the experimental condition, followed by a return to the treatment condition (B).
• ABABA design


  A design in which a baseline condition (A) is measured first, followed by measurements during a treatment condition (B), followed by a return to the baseline measurement condition (A), followed by a return to the treatment condition (B) and a final baseline measurement condition (A) to verify that the change in behavior is linked to the experimental condition.
• Baseline

  • A measure of behavior as it normally occurs without the experimental manipulation.
  • A control condition used to assess the impact of the experimental condition.
• Changing criterion design

  • A design used to modify behavior when the behavior cannot be changed all at once.
  • Instead, the behavior is modified in increments, and the criterion for success changes as the behavior is modified.
• Discrete trials design

  • A design that relies on presenting and averaging across many, many experimental trials.
  • Repeated applications result in a reliable picture of the effects of the independent variable.
• Large N design


  A design in which the behavior of groups of subjects is compared.
• Multiple baseline design

  • A small N design in which a series of baselines and treatments are compared.
  • Once established, however, a treatment is not withdrawn.
• Small N design

  • A design in which just one or a few subjects are used.
  • Typically, the experimenter collects baseline data during an initial control condition, applies the experimental treatment, then reinstates the original control condition to verify that changes observed in behavior were caused by the experimental intervention.