LAUSR

OBJECTIVES To investigate differential item functioning across the Spanish and English versions of the Orofacial Esthetic Scale (OES). METHODS OES data were collected from a consecutive sample of a total of 622 adult dental patients (311 English- and 311 Spanish-speaking adults) from HealthPartners dental clinics in Minnesota. We inspected boundary characteristic curves (BCCs) based on item response theory (IRT) in English and Spanish-speakers to examine differential item functioning (DIF). Using the Samejima's graded response model, we used the item response theory log-likelihood ratio (IRTLR) approach to test whether DIF was statistically significant. RESULTS Inspection of the BCCs did not reveal substantial differences in item difficulty and discrimination between English and Spanish-speakers. When IRTLR tests were performed for the seven OES items, no item was flagged with significant DIF after p-values were adjusted for multiple comparisons. CONCLUSIONS Pooling of Orofacial Esthetic Scale (OES) data from English and Spanish-speaking dental patients for analysis and interpretation is supported by the absence of differential item functioning (DIF) across the two language groups.