Assessment, Ahead of Print.
Despite the Heterosexist Harassment, Rejection, and Discrimination Scale (HHRDS) being a routinely used measure of discrimination, there is no current consensus regarding its fundamental psychometric properties. This study sought to: (a) test the dimensionality of the scale using a classical test theory approach, and (b), if lacking a clear multidimensional structure, use an item response theory approach to develop a concise unidimensional measure and examine differential item and test functioning across various identity factors. In a sample of sexual minority adults (N = 1,243), evaluation of the HHRDS supported a reduced 11-item unidimensional measure. Assessment of differential item functioning suggested differences for some items between cisgender men and cisgender women, cisgender men and gender-diverse individuals, gay/lesbian and bi+ individuals, and white/non-Latine individuals and people of color. However, differential item functioning had minimal impact on total test scores, supporting the use of the revised 11-item HHRDS across groups.