Single‐Participant Research Designs

Single-participant research designs involve the intensive study of one participant continuously or repeatedly across time. The participant may be a person or a single molar unit, such as an industrial organization or a political unit. As with conventional group designs based on reasonably large samples of subjects, single-participant designs are employed to determine whether different variables are related or whether a treatment or intervention causes some effect on relevant response measures. There are situations in which it is more meaningful, more convenient, more ethical, and/or less expensive to study one or very few participants intensively than to study many participants. A basic difference between group and single-participant designs is that one or very few observations are generally obtained from each participant with group designs, whereas many observations are usually obtained from a single participant across time in the case of single-participant designs. The design categories of correlational, quasi-experimental, and experimental, which are frequently used to classify different types of group designs, can also be used to classify various single-participant designs. Keywords: experimental design; research methodology; scientific method