Factor structure and psychometric properties of the Brief Symptom Inventory-18 in women: a MACS approach to testing for invariance across racial/ethnic groups.

This study used data from 3 sites to examine the invariance and psychometric characteristics of the Brief Symptom Inventory-18 across Black, Hispanic, and White mothers of 5th graders (N = 4,711; M = 38.07 years of age, SD = 7.16). Internal consistencies were satisfactory for all subscale scores of the instrument regardless of ethnic group membership. Mean and covariance structures analysis indicated that the hypothesized 3-factor structure of the instrument was not robust across ethnic groups. It provided a reasonable approximation to the data for Black and White women but not for Hispanic women. Tests for differential item functioning (DIF) were therefore conducted for only Black and White women. Analyses revealed no more than trivial instances of nonuniform DIF but more substantial evidence of uniform DIF for 3 of the 18 items. After having established partial strong factorial invariance of the instrument, latent factor means were found to be significantly higher for Black than for White women on all 3 subscales (somatization, depression, anxiety). In conclusion, the instrument may be used for mean comparisons between Black and White women.