This study examined different methods of combining data from a well established rating scale – the Disruptive Behavior Disorders Rating Scale (DBDRS) – with data from a well established interview – the computerized self report version of the Diagnostic Interview Schedule for Children for DSM-IV (P-DISC-IV) – when examining parent report of ADHD. These measures were completed for 80 children who participated in a summer camp for children with disruptive behavior. Results showed significant overlap between the two diagnostic measures but parent report on the DBDRS was more highly associated with children’s camp behaviors than was parent report on the P-DISC-IV. In addition, combining ratings and interview data using an “either/or” rule was more highly associated with camp behavior than was combining data using a “both/and” rule. Results suggest there may be little additional value of adding data from parent self-report on the computerized version of the P-DISC-IV to behavior rating data.