Measurement Invariance of the Sexual Orientation Microaggression Inventory across LGB Males and Females in Taiwan: Bifactor Structure Fits the Best

The present study examined the factor structure and concurrent validity of the traditional Chinese version of the Sexual Orientation Microaggression Inventory (SOMI) among lesbian, gay, and bisexual (LGB) individuals in Taiwan. In total, 1000 self-identified LGB individuals completed the SOMI, HIV and Homosexuality Related Stigma Scale (HHRSS), and Acceptance and Action Questionnaire-II (AAQ). Different factor structures (including one-factor, four-factor, bifactor, and higher-order factor structures) were evaluated using confirmatory factor analysis. The bifactor structure significantly outperformed all others on the SOMI. The bifactor structure with one general factor and four trait factors was found to be measurement invariant across biological sex with satisfactory fit indices. The SOMI general factor was significantly associated with HHRSS-Homosexuality score and AAQ score. The findings indicate that the SOMI is a psychometrically sound instrument for Taiwan sexual minority groups. More specifically, SOMI can be used to accurately assess microaggression among LGB individuals. The measure on microaggression may also provide insights for healthcare providers about LGB individuals’ sexuality-related stigma. Moreover, healthcare providers and relevant stakeholders can use the SOMI to understand how LGB individuals perceive and feel microaggression.