Abstract:
The present study sought to examine the items of the revised of the Sociosexual Orientation Inventory (SOI-R) for gendered differential item functioning (DIF) using the multiple indicators, multiple causes (MIMIC) model. Because previous research indicates that men and, to a greater extent, women accommodate their responses on items assessing sexual attitudes and behaviors to conform to gender norms, it was hypothesized that the items comprising the attitude and behavior subscales of the SOI-R would exhibit DIF favoring men. This would suggest that men had a higher probability than women of endorsing higher item response categories, after being matched on total SOI-R scores. The items comprising the desire subscale were also examined for DIF, although no specific hypotheses were made for these items. A full multidimensional item response theory (MIRT) analysis was also performed on the scale and the parameters of the best fitting model utilized in the interpretation of DIF results. The results of the MIRT analyses determined that the graded response model (GRM) fit the data best. Discrimination and threshold parameters revealed that most items of the SOI-R were good at differentiating individuals with various sociosexual orientations and provided a large degree of information for individuals with typical levels of the trait. MIMIC results revealed that seven of the nine items exhibited DIF. However, contrary to predictions, six of these items demonstrated DIF favoring women. While
the results of this study do not provide insight into why women needed less of the latent trait than men to endorse higher item responses, it is theorized that selection bias may play a role.
