Statistical Alternatives for Single-Case Designs
This chapter discusses statistical approaches for analyzing single-case research designs.1 These designs and their corresponding statistical an alyses span a continuum that ranges from experimental designs to cor relational designs. Figures 6.1a and 6.1b display a typology of analyses. By experimental designs we mean designs in which researchers manipu late one or more independent variables and in which potentially con founding variables are controlled by randomly assigning treatment con ditions to subjects. In quasi-experimental designs, the independent variables are manipulated by natural or historical events. Consequently, there is little direct control of unwanted variation, and treatments are not assigned at random. As one departs from the strict requirements of experimental designs, it becomes more difficult to draw precise conclu sions about causal relations between manipulations and outcomes.