This chapter presented an overview of the characteristics of single-system designs, and some of the complications and threats to their design validity and their generalizability. Designs are used for...

This chapter presented an overview of the characteristics of single-system designs, and some of the complications and threats to their design validity and their generalizability. Designs are used for one or both of two major purposes: to describe change in target problems, and possibly, to infer that intervention was causally related to that observed change. Some designs also can be used to compare two interventions with each other. Designs are the arrangements of observations made before, during, and/or after interventions through which these questions may be logically addressed.