Definitions:
Reversal Design: any experimental design in which the researcher attempts to verify the effects of the independent variable by “reversing” responding to a level obtained in a previous condition; encompasses experimental designs in which the independent variable is withdrawn (A-B-A-B) or reversed in its focus [e.g. DRI/DRA] (Cooper, Heron, & Heward, 2007).
Withdrawal Design: often used as a synonym for A-B-A-B design; also used to describe experiments in which an effective treatment is sequentially or partially withdrawn to promote the maintenance of behavior changes (Cooper, Heron, & Heward, 2007).