Ethnic identification biases responses to the Padua Inventory for obsessive-compulsive disorder

The authors report differential item functioning (DIF) between Black and White participants completing the 60-item Padua Inventory (PI) for obsessive-compulsive disorder (OCD). The authors use an Internet-generated sample that included 105 Blacks, 67 Hispanics, 582 Whites, and 136 additional participants reporting an OCD diagnosis. Factor analysis replicated prior work indicating the PI consists of four factors: contamination fears, checking behaviors, impaired control over thoughts, and fear of losing control over impulses. On the contamination subscale, nonclinical Black and Hispanic mean scores were as high as the OCD group. Comparing Blacks to Whites, the authors applied an item response theory, DIF-graded response model to each factor and found significant DIF on eight items, with biased items in each factor. Results suggest that extraneous factors contribute to racial differences on scores. Cultural practices and fear of being negatively stereotyped may contribute to item bias.