Measuring participation as defined by the World Health Organization in the International Classification of Functioning, Disability and Health : psychometric properties of the Ghent Participation Scale

Objective: To examine the internal consistency, test-retest reliability, construct validity, discriminant validity and responsiveness of the Ghent Participation Scale. Design: Cross-sectional study with a test-retest sample. Setting: Six outpatient rehabilitation centres in Belgium. Subjects: A total of 365 outpatients from eight diagnostic groups. Measures: The Ghent Participation Scale, the Impact on Participation and Autonomy, the Utrecht Scale for Evaluation of Rehabilitation-Participation and the Medical outcome study Short Form SF-36. Results: The Ghent Participation Scale was found to have good internal consistency (Cronbach's between 0.75 and 0.83). At item level, the test-retest reliability was good; weighted kappas ranged between 0.57 and 0.88. On the dimension level intraclass correlation coefficients ranged between 0.80 and 0.90. Evidence for construct validity came from high correlations between the subscales of the Ghent Participation Scale and four subscales of the Impact on Participation and Autonomy (range, r=-0.71 to -0.87) and two subscales of the Utrecht Scale for Evaluation of Rehabilitation-Participation (range, r=0.54 to 0.72). Standardized response mean ranged between 0.23 and 0.68 and the area under the curve ranged between 68% and 88%. Conclusion: The Ghent Participation Scale appears to be a valid and reliable method of assessing participation irrespective of the respondent's health condition. The Ghent Participation Scale is responsive and is able to detect changes over time.