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Aims: To assess the differential item functioning (DIF) of the Jaw Functional Limitation Scale (JFLS) due to gender, age, and language (English vs Spanish). Methods: JFLS data were collected from a consecutive sample of 2,115 adult dental patients from HealthPartners dental clinics in Minnesota. Participants with missing data were excluded, and analyses were performed using data from 1,678 participants. Whether the item response theory (IRT) model assumptions of essential unidimensionality and local independence held up for the JFLS was examined. Then, using Samejima's graded response model, the IRT log-likelihood ratio approach was used to detect DIF. The magnitude and impact of DIF based on Raju's noncompensatory DIF (NCDIF) cutoff value of 0.096, Cohen's effect sizes, and test (or scale) characteristic curves were also assessed. Results: Essential unidimensionality was confirmed, but locally dependent items were found on the JFLS. A few items were flagged with statistically significant DIF after adjustment for multiple comparisons. The NCDIF indices associated with all DIF items were < 0.096, and they had small effect sizes of ≤ 0.2. The differences between the expected scores shown in the test characteristic curves were little to none. Conclusion: The present results support the use of the JFLS summary score to obtain psychometrically robust score comparisons across English- and Spanishspeaking, male and female, and younger and older dental patients. Overall, the magnitude of DIF was relatively small, and the practical impact minimal. [ABSTRACT FROM AUTHOR]

Objectives: a) To evaluate the item and scale properties of the Oral Health Literacy Adults Questionnaire (OHL‐AQ) in an adult general population. b) To determine precision or accuracy of the respondents' estimated scores along the Oral Health Literacy (OHL) spectrum using item response theory (IRT) modeling. Methods: Survey data were collected from a convenience sample of 405 adult attendees of the 2014 Minnesota State Fair. We used the two‐parameter logistic (2PL) model for the item response theory (IRT) analyses of OHL‐AQ data and calibrated items to estimate model‐based item difficulty and discrimination parameters. Item and scale properties were also assessed by plotting and interpreting item characteristic curves (ICCs), test characteristic curve (TCC), and test information function (TIF). Results: Based on interpretation of model coefficients, statistical testing, and model fit criteria, we deemed the 2PL model superior and selected this model to examine item and scale properties. Scale reliability was shown to be good through the test information function (TIF). TIF from our analysis showed that higher levels of OHL were measured less precisely than lower levels of OHL. Conclusion: We demonstrated OHL‐AQ as a whole has promising psychometric properties. However, for equiprecise measurement across the scale range, the scale needs more items for measuring higher levels of OHL. [ABSTRACT FROM AUTHOR]

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 speakers 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 speakers 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. [ABSTRACT FROM AUTHOR]