This study utilized a multiple baseline design across participants with an embedded ABA design for Ashley and an
embedded ABACA design for Vince and Colt. During all ‘‘A’’ phases,the participant had access to one set oftoys at a time in the
therapy room. Data were collected on appropriate play and stereotypy but intervention was not delivered. During ‘‘B’’
phases, a play skills intervention was implemented in the classroom with only the intervention toy set. After appropriate
play increased, the participant was returned to baseline conditions (second ‘‘A’’ phase) to assess generalization of play skills
across toys and settings. If play skills did not generalize during the return to baseline, as was the case for Colt and Vince, lag
schedules of reinforcement were added to the behavioral intervention in Phase ‘‘C’’. Following phase ‘‘C’’, generalization of
play and stereotypy were assessed again in the last return to baseline phase. Maintenance was then assessed at four, six, and
eight weeks for all three participants