Applying the Taxonomy of Validity Threats from Mainstream Research Design to Single-Case Experiments in Applied Behavior Analysis.

Mainstream research design in the social and behavioral sciences has often been conceptualized using a taxonomy of threats to experimental validity first articulated by Campbell and his colleagues (Campbell & Stanley, 1966; Cook & Campbell, 1979). The most recent update of this framework was published by Shadish, Cook, and Campbell (2002), in which the authors describe different types of validity and numerous threats to each primarily in terms of group-design experiments. In the present article, we apply Shadish et al.'s analysis of threats to internal, external, statistical conclusion, and construct validity to single-case experimental research as it is typically conducted in applied behavior analysis. In doing so, we hope to provide researchers and educators in the field with a translation of the validity-threats taxonomy into terms and considerations relevant to the design and interpretation of applied behavior-analytic research for the purposes of more careful research design and the ability to communicate our designs to individuals outside of behavior analysis, using their own vocabulary.