Reliability of the Gross Motor Performance Measure

BACKGROUND AND PURPOSE: The reporting of reliability coefficients and the method of their determination is expected of test developers. The purpose of this study was to estimate the interrater, intrarater, and test-retest reliability of the Gross Motor Performance Measure, a measure of quality of movement designed to accompany the Gross Motor Function Measure. SUBJECTS: Subjects were 28 children (25 with cerebral palsy, 2 nondisabled, 1 with head injury) between the ages of 1 and 10 years. METHODS: Reliability data were obtained from assessments of 19 therapists. RESULTS: Intraclass correlation coefficients for reliability varied from .92 to .96 for the total scores and from .84 to .94 for the five attribute scores. CONCLUSION AND DISCUSSION: When the Gross Motor Performance Measure was administered by therapists who are familiar with the Gross Motor Function Measure and had a 1-day training workshop, reliability of the total scores was above recommended minimums. Scores of single attributes were less reproducible.