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 5 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 in-formation) 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.