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.
Bibliographical noteFunding Information:
Swaha Pattanaik and Mike T. John were supported by the National Institute of Dental and Craniofacial Research of the National Institutes of Health, USA, under Award Number R01DE028059. The authors thank Kathleen Patka, Executive Office and Administrative Specialist, Division of Oral Medicine, School of Dentistry, University of Minnesota, Minneapolis, MN, USA, for proofreading and editing the manuscript.
© 2020 American Association of Public Health Dentistry
- dental patient-reported outcomes
- dental patient-reported outcomes measures
- item response theory
- oral health literacy
- psychometric evaluation