Psychometric Properties of the Disability Identity Development Scale: Confirmatory Factor and Bifactor Analyses

Purpose/Objective: This work provides comprehensive analyses targeting the factor structure and dimensionality of the Disability Identity Development Scale (DIDS). In Forber-Pratt et al., 2020, disability was defined broadly to include individuals with visible or hidden disabilities across many disability groups (i.e., physical, intellectual, learning, or chronic illness). Research Method/Design: Retained items from previous exploratory factor analysis were administered to a sample of adults with disabilities (n = 1,126) ranging in age from 18–78 years. Confirmatory factor analytics (CFA) including traditional CFA, and bifactor confirmatory analyses were used to examine the dimensionality and structure of the DIDS. Results: Traditional CFA provided lack of evidence in support of the oblique four-factor structure previously reported. Bifactor confirmatory analysis revealed items on the DIDS are consistent with unidimensional, and to a lesser degree multidimensional solutions (i.e., items lacked a level of content diversity to substantiate a complex, reliable multifactor structure). Discussion/Conclusion: Analytic results on the DIDS revealed reasonable psychometric properties as a measure of disability identity. Our results support using a sum or total score of disability identity. Results of this work are an important contribution to a growing body of literature supporting, and investigating, disability identity development. Furthermore, the DIDS measure with its resulting composite score of disability identity has the potential to inform clinicians in the field of rehabilitation psychology as well as informing future targeted interventions