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Single Subject Design

From Wikipedia, the free encyclopedia


Single-subject design or single-case research design is a research design most often used in applied fields of psychology, education, and human behavior in which the subject serves as his/her own control, rather than using another individual/group. Researchers use single-subject design because these designs are sensitive to individual organism differences versus group designs, which are sensitive to averages of groups. Often there will be large numbers of subjects in a research study using single-subject design, however—because the subject serves as their own control, this is still a single-subject design. These designs are used primarily to evaluate the effect of a variety of interventions in applied research. 

Single Subject Designs (visual) 

A-B Single Subject Design

A-B-A / Withdrawal Design

A-B-A-B Reversal

behavior to decrease

behavior to increase

Changing Criterion Designs

Multiple Baseline (MBL) Across Participants

Alternating Treatment (Alt-Tx) Design 

Resources