A total of 43 reports was eligible for inclusion. Thosereports used one or both of two research designs: lon-gitudinal designs examining changes for a single groupof participants over time (32 studies) and contrast groupdesigns comparing changes in treatment (leavers) andcontrast groups over time (stayers; 15 studies). Six stud・ies incorporated both longitudinal and contrast groupdesigns. Some of the studies reported overall adap-tive behavior and/or overall challenging behavior (seeTables 1 and 3), whereas others reported only specificadaptive or challenging behavior domains (see Tables 2and 4). Some studies reported both types of outcomes.