Validity of Goal Attainment Scaling in Infants With Motor Delays

BACKGROUND AND PURPOSE: The purpose of this study was to examine (1) content validity of goal attainment scaling (GAS), (2) the responsiveness of GAS compared with a behavioral objective, and (3) concurrent validity of GAS and the Peabody Developmental Gross Motor Scale. SUBJECTS AND METHODS: Two motor goals were developed for two consecutive 3-month periods for 21 infants with motor delays. The goals were put into behavioral objective and GAS formats and scored by independent examiners. Content validity was examined by having 10 physical therapists rate 10 randomly selected GAS-formatted goals on three dimensions: (1) the importance of the goal for motor development and function, (2) whether the expected progress was achievable, and (3) whether each of the four levels of change was clinically important. RESULTS: Between 77% and 88% of the therapists' ratings for each dimension met the criterion for content validity. The ratings did not differ significantly among the therapists for any of the three dimensions. Change that could not be measured with the behavioral objective format was measured with the GAS format for 61% of the goals, including 73% of the goals in which the behavioral objective was achieved. Correlations between GAS T-scores and Peabody gross motor age-equivalent change scores were not significant. CONCLUSION AND DISCUSSION: The results support content validity and the responsiveness of GAS, and provide evidence that GAS and the Peabody Scale measure different aspects of motor development. Goal attainment scaling is recommended for use in clinical practice and in treatment outcomes research.