Single subject designs rely on the application of treatment to a single subject or group of single subjects in order to determine treatment effects. It can be used to determine the effects of Pavlov’s classical conditioning, including baseline, treatment, extinction, and spontaneous recovery. It can also be used to determine the effects of the same treatment on different subjects, different treatments on different subjects, and even different treatments on the same subject.
Multiple baselines go beyond the simple A-B-A-B designs and control for more variables, providing a better understanding of the outcome as well as increased generalizability to the population at large. With multiple baseline designs, a time-lagged approach can be used to determine if the introduction of the treatment is actually causing the change in behavior.
Single subject designs are often considered the research method of choice for behavioral research attempting to measure changes in behavior due to the application of reinforcement. It provides a powerful means for teachers to determine the most effective reward or discipline technique for a specific student or for managers to determine the best method of compensation or reward. However, the issue of generalizability is significant. Can we truly say that if the treatment causes a change in a single subject or even a small group of single subjects that this change will also occur within the whole population? Generalizability, often a major concern in research, is addressed in chapter 5.