A number of experimental designs are suited for use in single-subject design research conducted with individuals with intellectual and developmental disorders. Single-subject design is an approach to demonstrating experimental control in which each subject serves as his or her own control, which is distinct from case study research and also from group-design research. This entry describes one such single subject research design: the multiple baseline design (MBL). First, the entry describes the MBL, reviews conditions under which it is used, and examines variations of the MBL. Second, the entry presents considerations for MBLs.

An MBL is an experimental design in which an intervention is introduced sequentially across more than one (usually three or more) vertically arranged panels (or baselines) that each depict a time series responding ...