How Well Does the Index of Race-Related Stress-Brief Function in a Trauma-Exposed Black Community Sample? An Item Response Theory Examination of Discrimination and Difficulty Parameters

Background: Race-related stress negatively impacts the mental health of Black Americans to a greater degree than other racialized groups. Additionally, trauma exposure is associated with more severe levels of posttraumatic stress disorder for individuals who also experience race-related stress. Therefore, an accurate assessment of race-related stress in a trauma-exposed sample of Black Americans is necessary to ensure the validity and reliability of empirical findings regarding race-related stress and intervention efficacy. The Index of Race-Related Stress (IRRS) is one of the most commonly used measures to assess race-related stress among Black Americans. Due to a lack of psychometric support for the abbreviated version of IRRS-brief (IRRS-B) on a trauma-exposed sample of Black Americans, our study aims to address this gap in literature. Method: We used item response theory (IRT) to assess item difficulty, discrimination, and factor structure in a sample of trauma-exposed Black Americans (n = 226). We employed a multidimensional graded response model with corresponding items loaded on to the three previously established factors of the IRRS. Results: The most discriminating items asked about observing harsh treatment of Black individuals, experiencing less courtesy in establishments, and being stared at as though you do not belong. The item with the lowest difficulty described negative media representation of Black individuals while the item with the highest difficulty described lack of positive media portrayals of Black Americans. Discussion: These results indicate that items varied considerably in the degree to which they adequately captured race-related stress. Future research should use IRT with newly worded questions to further improve the assessment of race-related stress in Black Americans.