Measurement Invariance across Sexual Orientation for Measures of Sexual Attitudes.

Despite the growing interest in the study of sexual attitudes across sexual orientation, few studies have tested whether the instruments used to measure them are invariant. This study examined measurement invariance (configural, weak, strong, and strict) across sexual orientation in three different sexual attitude scales: the Sexual Opinion Survey (SOS) to assess erotophilia, the Hurlbert Index of Sexual Fantasy (HISF) to assess attitudes toward sexual fantasies, and the Negative Attitudes Toward Masturbation Inventory (NATMI) to assess negative attitudes toward masturbation. A total of 2293 Spanish adult men and women with different sexual orientations (i.e., heterosexual, bisexual, and gay) participated in the study. The results indicated strict invariance for HISF across sexual orientation and only weak invariance for SOS and NATMI. Differential item functioning was also found in two items of the NATMI scale. Evidence of validity was provided for the three scales that were studied.