Brown, Mapy Chavez.

Research has shown that applied behavior analysis is an effective methodology for instruction of children with autism. Furthermore, recent research has indicated a direct correlation between autism severity level and response accuracy under different verbal discriminative stimulus conditions used in the antecedent portion of a discrete instructional trial. This study was conducted to further investigate the relationship between autism severity level and response accuracy under different verbal discriminative stimulus conditions using the Gilliam Autism Rating Scale (GARS) to measure the autism severity of four prekindergarten students who were being served in home-based applied behavior analysis programs. Response accuracy was assessed under two experimental conditions for each participant: simplified speech and typical speech, using an alternating treatments design. These results are presented and discussed in relation to improving the effectiveness of early intervention program.