Chinese SF-36 Health Survey: translation, cultural adaptation, validation, and normalisation

Study objective: To develop a self administered Chinese (mainland) version of the Short-Form Health Survey (SF-36) for use in health related quality of life measurements in China. Design: A three stage protocol was followed including translation, tests of scaling construction and scoring assumptions, validation, and normalisation. Setting: 1000 households in 18 communities of Hangzhou. Participants: 1688 respondents recruited by multi-stage mixed sampling. Main results: The assumption of equal intervals was violated for the vitality and mental health scales. The recoded item values were used to calculate scale scores. The clustering and ordering of item means was the same as that of the source and other two Chinese versions. The items in each scale had similar standard deviations except those in the physical functioning, boduily pain, social functioning scales. The item hypothesised scale correlations were identical for all except the social functioning and vitality scales. Convergent validity and discriminant validity were satisfactory for all except the social functioning scale. Cronbach’s α coefficients ranged from 0.72 to 0.88 except 0.39 for the social functioning scale and 0.66 for the vitality scale. Two weeks test-retest reliability coefficients ranged from 0.66 to 0.94. Factor analysis identified two principal components explaining 56.3% of the total variance. The Chinese SF-36 could distinguish known groups. Conclusions: This study suggested that the Chinese (mainland) version of the SF-36 functioned in the general population of Hangzhou, China quite similarly to the original American population tested. Caution is recommended in the interpretation of the social functioning and vitality scales pending further studies.