Interrater reliability of goal attainment scaling in rehabilitation of children with cerebral palsy

Abstract

Objectives: To determine the interrater reliability of Goal Attainment Scaling (GAS) in the routine practice of interdisciplinary rehabilitation of children with cerebral palsy, and to examine the difference in the interrater reliability of the scores between GAS scales constructed by the children's own therapists and the scales constructed by independent therapists.

Design: Individually tailored GAS scales, based on predetermined criteria, were constructed at the start of a 6-month rehabilitation period. The outcome was rated independently by 2 therapists at the end of the treatment period. Two different data sets were acquired, one consisting of scores on GAS scales constructed by the children's own therapists, the other of scores on GAS scales constructed by matched independent raters of the same profession.

Setting: A children's unit of a medium-sized rehabilitation center in The Netherlands.

Participants: Physical therapists (n=8), occupational therapists (n=8), and speech therapists (n=4) participated in pairs. They constructed 2 sets of 64 GAS scales each, for 23 children with cerebral palsy.

Interventions: A 6-month interdisciplinary pediatric rehabilitation program.

Main outcome measure: Interrater reliability was assessed using linear-weighted Cohen's kappa.

Results: The scales constructed by the children's therapists had an interrater reliability of .82 (95% confidence interval [CI], .73-.91). The interrater reliability for scales constructed by the independent raters was .64 (95% CI, .49-.79). The main reason for disagreement between raters was discrepancies in the professionals' interpretation of the children's capacities versus their actual performance during assessment.

Conclusions: The interrater reliability of GAS used under optimal conditions was good, particularly for scales constructed by the children's own therapists.