Interrater reliability and content validity of a minimal data set to measure outcomes of students receiving school-based occupational therapy and physical therapy.

BACKGROUND AND PURPOSE: The 1997 Amendments of the Individuals with Disabilities Education Act increased the emphasis on accountability for outcomes of students with disabilities in the United States. The purpose of this study was to determine the content validity and estimate the interrater reliability of the School Outcomes Measure, a new minimal data set to measure groups of students' performance in the areas addressed by school-based therapy.

METHOD: Forty-five occupational therapists and physical therapists working in Oklahoma's public schools participated in the content validity study. Eight occupational therapist-physical therapist pairs rated 17 students for the interrater reliability study. Therapists were recruited and data were collected by mail for both studies.

RESULTS: Most validity study participants thought the tool was comprehensive and clear, and that they could complete the tool twice a year for their students. The weighted kappa statistic indicated that the therapists' agreement was substantial (.73) to almost perfect (.96) for 25 of the 28 student functional status items.

DISCUSSION: The results support the content validity and interrater reliability of the items. This study was an initial step in development of the tool and further studies are needed in the validation process.