psychometric properties and hierarchical factor structure of short form health survey scale (sf-36) in a non-clinical sample

aim and background: in this study, the psychometric properties and hierarchal structural validity of short form health survey scale (sf-36) among students using structural equating modeling was investigated. methods and materials: a sample with 310 students (158 male and 152 female) from tehran university were chosen by multistage sampling method. for verifying discernment validity, two clinical sample groups were used. first group had 52 patients with physical disease and second clinical group had 58 students with psychological disorder diagnostics, which were selected from university health centers. to calculate the convergence and divergence validity, the sf-36 was administered and at the same time, the university student depression inventory (usdi), student-life stress inventory (sisi), oxford happiness scale (ohs), mental health inventory (mhi), and social support (ss), in nonclinical sample was investigated. the first, second, and third hierarchical factorial structure of sf-36 scale was estimated by weighted least squares method, and sufficiency of model fitness was evaluated according to the root mean square residual, root mean square error of approximation, comparative fit index, adjusted goodness of fit index, goodness of fit index, χ 2 /df, and δχ 2 indices. findings: the chornbach’s alpha coefficients in all subscales were satisfactory and higher than 0.70. the factor structure of sf-36 scale was confirmed using confirmatory factor analysis in eight dimensions of first order including physical performance, physical role performance, body pain, general health, vitality, social functioning, emotional role performance and mental health. based on correlation matrix, the sf-36 scale had negative correlation with depression and stress and positive correlation with happiness, mental health, and social support, which imply satisfactory convergent and divergent validity of sf-36 scale. conclusions: the eight first-order and three second-order factor structure showed better fit with the observed data compared with two second-order and one third-order factor structure of sf-36 scale. the confirmatory factor structure, reliability, and validity of sf-36 scale were acceptable for research and clinical diagnostics application.