A Psychometric Evaluation of the Intrasexual Competition Scale

The Intrasexual Competition Scale (ICS) measures the extent to which individuals view their interaction with same-sex others in competitive terms. Although it is frequently used in studies investigating differences in mating behavior, the factor structure of the ICS has never been confirmed. Researchers have yet to use multiple-group confirmatory factor analysis to test whether the properties of the scale are equivalent between the sexes. In Study 1, we report on an investigation in which participants' responses to the ICS were submitted to exploratory factor analysis (EFA). In Study 2A, we compared the fit of one and two-factor models from the EFA as well as two additional models, using confirmatory factor analysis with an independent sample. The best fit was obtained by a two-factor solution, which reflected: (1) respondents' feelings of frustration when intrasexual competitors are better off (Inferiority Frustration), and (2) respondents' enjoyment of being better than intrasexual competitors (Superiority Enjoyment). This model achieved a high degree of measurement invariance. In Study 2B, we found the ICS had good concurrent validity via associations with sociosexuality, mating effort, and sexual behavior. Together, these analyses suggest that the ICS is a valid measure of intrasexually competitive attitudes.