Cross-Ethnic Invariance of BSI-18 in Individuals With Serious Mental Illness: New Perspectives on Measurement Invariance Testing

Objective: This study examines the psychometric properties of the Brief Symptom Inventory 18 (BSI-18), a measure of psychological distress, across European Americans, African Americans, and Latinos (N = 1,166) with serious mental illnesses. It also critiques traditional practices for evaluating measurement invariance and suggests new strategies (e.g., use of equivalence testing, incorporation of effect size information) for evaluating invariance. Method: To evaluate unidimensionality across different ethnic groups, we used confirmatory factor analysis followed by invariance testing with forward and backward approaches. Results: We explored ethnic differences in the correlational structure of the four BSI-18 subscales (depression, somatization, anxiety, and panic) and ethnic differences in mean levels of the subscales. We found no strong evidence for differences in psychometric properties of the BSI-18 across ethnic groups. Conclusions: The BSI-18 showed reasonable evidence of invariance across ethnic groups. Expanded methods for invariance testing should be considered in place of the more traditional methods.