Reliability of translation of the RAND 36-item health survey in a post-rehabilitation population
The aim of this study is to evaluate the reliability of the RAND 36-item Health survey as a measure of health-related quality of life in a general Dutch post-rehabilitation population. A total of 752 ex-rehabilitation patients were invited to complete the Dutch RAND 36-item health survey. After 2 weeks, the people who responded to the first questionnaire were asked to complete the same questionnaire again. Internal consistency of the questionnaire was expressed as Cronbach’s α. Test–retest reliability was expressed as intraclass correlation coefficient (ICC) and presented in Bland–Altman plots. Internal consistency was found acceptable for all subscales (n=276; Cronbach’s α ranged from 0.81 to 0.95). Test–retest reliability was found acceptable for research and group comparisons for all subscales (n=184; ICC ranged from 0.71 to 0.88). Overall, test–retest reliability of the physical functioning (ICC=0.86), pain (ICC=0.87), and general health (ICC=0.88) subscale was relatively high, and that of health change (ICC=0.71) was relatively low. Reliability of the questionnaire did not notably differ between participants who indicated stable health and participants who indicated health change during the past weeks. In conclusion, the Dutch translation of the RAND 36-item health survey is reliable for research and group comparisons in a general post-rehabilitation population. However, the RAND 36-item health survey is not sufficiently reliable for individual comparisons within this population.