Table 1.

Several single-case designs, including general procedures, advantages, and disadvantages

Design	Procedure	Advantages	Disadvantages
Reversal (ABA, ABAB)	Baseline conducted, treatment is implemented, and then treatment is removed	Within-subject replication; clear demonstration of an intervention effect in one subject	Not applicable if behavior is irreversible, or when removing treatment is undesirable
Multiple baseline (interrupted time series, stepped wedge)	Baseline is conducted for varying durations across participants, then treatment is introduced in a staggered fashion	Treatment does not have to be withdrawn	No within-subject replication. Potentially more subjects needed to demonstrate intervention effects than when using reversal design
Changing criterion	Following a baseline phase, treatment goals are implemented. Goals become progressively more challenging as they are met	Demonstrates within-subject control by levels of the independent variable without removing treatment; Useful when gradual change in behavior is desirable	Not applicable for binary outcome measures—must have continuous outcomes
Combined	Elements of any treatment can be combined	Allows for more flexible, individually tailored designs	If different designs are used across participants in a single study, comparisons across subjects can be difficult