Measuring participation based on the insiders and the outsiders perspective

Introduction/Background: Despite the consensus on the importance of participation as an outcome measure of rehabilitation a lot of problems remain in the operational application of the concept. There is still a need for a comprehensive participation measure combining the insiders and the outsiders perspective of the patient. Therefore a new participation measure, the GPS (The Ghent Participation scale) has been developed. Material and Methods: Objective: To examine the psychometric of the Ghent Participation Scale (GPS). Design: Cross sectional study with a test-retest sample. Patients: 365 former rehabilitation outpatients from 8 diagnostic groups in 6 rehabilitation centers. Material: The GPS and the IPA (Impact on participation and autonomy), the USER-Participation (The Utrecht Scale for Evaluation of Rehabilitation Participation - USER) and the SF-36 (Medical outcome study Short Form). Results: The GPS addresses participation in 3 dimensions: (1) performing activities according to preferred choices and wishes, (2) performing activities leading to social appreciation and acceptance (3) the need to delegate activities. The GPS shows a good internal consistency (Cronbach’s α between 0.752 and 0.83). On item level, the test retest reliability was good, weighted kappa’s ranged between 0.57 and 0.88. On the dimension level: intraclass correlation coefficients (ICC) ranged between 0.80 and 0.90. The construct validity was supported by high correlations between subscales form the GPS and 4 subscales of the IPA (range, r= -0.71 to -0.87) and 2 subscales of the USER-P (range, r= 0.54 to 0.72). Standardized response mean (SRM) ranged between 0.23 and 0.68 and the Area Under the Curve (AUC) ranged between 68 and 88%. Conclusion: The GPS appears to be a reliable and valid measure to rate participation irrespective of the individual’s health condition. The GPS is responsive and is able to detect changes over time.