Psychometric properties of ADHD rating scales among children with mental retardation I: reliability.

The reliability of Attention-Deficit/Hyperactivity Disorder (ADHD) rating scales in children with mental retardation was assessed. Parents, teachers, and teaching assistants completed ADHD rating scales on 48 children aged 5-12 diagnosed with mental retardation. Measures included the Child Behavior Checklist (CBCL), Conners Rating Scales, the Attention-Deficit/Hyperactivity Disorder Test (ADHDT), the Swanson, Nolan, and Pelham (SNAP) Checklist, the Werry-Weiss-Peters Activity Rating Scale (WWPARS), the ADD-H Comprehensive Teacher's Rating Scale (ACTeRS), and the Aberrant Behavior Checklist-Community (ABC-C). The internal consistency, test-retest, and interrater reliability of each scale was examined. Results showed best support for teacher completed scales, followed by ratings made by teaching assistants, and parent-report scales. Strong support for the internal consistency of the teacher-report measures was found, and it was quite similar to previously reported internal consistencies with typically developing children. Test-retest reliabilities of the teacher report measures were also quite good but tended to be lower than those reported for typically developing children. For teaching assistant ratings, test-retest reliabilities were adequate to very good. The internal consistency reliabilities for parent completed measures were adequate to excellent, but test-retest reliabilities were low. Interrater reliability was best for teacher-teaching assistants. The ABC-C was the only measure on which the interrater reliability was adequate for clinical purposes.