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ABA and ABAB Designs

  1. Roger E. Kirk

Published Online: 30 JAN 2010

DOI: 10.1002/9780470479216.corpsy0001

Corsini Encyclopedia of Psychology

Corsini Encyclopedia of Psychology

How to Cite

Kirk, R. E. 2010. ABA and ABAB Designs. Corsini Encyclopedia of Psychology. 1.

Author Information

  1. Baylor University

Publication History

  1. Published Online: 30 JAN 2010


Single-case designs are often used to assess the effects of an intervention. The designs usually focus on one participant who is observed numerous times. Large-sample designs, by comparison, use many participants who are observed only a few times. The simplest single-case design is the AB design. The letter A denotes a baseline phase during which no intervention is in effect; the letter B denotes the intervention phase. The baseline phase serves three purposes. It provides data about a participant's performance prior to instituting an intervention, it provides a basis for predicting a participant's future performance in the absence of an intervention, and it indicates the normal variability in the participant's performance.