Psychometric assessment of HIV sexual risk scale among MSM: A Rasch model approach

Background/ Objectives: The purpose of this study was to apply the Rasch model on psychometric assessment of HIV sexual risk scale among men who have sex with men (MSM). Methods: A cross-sectional study using respondent driven sampling was conducted among 351 MSM in Shenzhen, China. HIV-sexual risk was measured in 9 types of sexual behaviors that included unprotected anal or oral intercourse, commercial sex and concurrent sexual partnerships. . The Rasch model was used to examine the psychometric properties of HIV sexual risk scale among MSM. Results: The Rasch analysis of the 9 items met the unidimensionality and local independence assumption. The fit statistics provided acceptable infit and outfit values. Item difficulty invariance analysis showed that the item estimates of the risk behavior items were invariant (within error). Although the person reliability was low at 0.35, the item reliability was rather high at 0.99. Conclusions: The Rasch model can be utilized for measuring the level of sexual risk for HIV infection as a single latent construct and for establishing the relative degree of severity of each type of sexual behavior in HIV transmission and acquisition among MSM. The measurement scale provides a useful measurement tool to inform, design and evaluate behavioral interventions for HIV, which can be a valuable resource in the assessment of sexual behaviors among MSM in China and other similar countries.