Quality of Life Research Supplement: Applying Item Response Theory to Enhance Health Outcomes Assessment

Based on a 2004 conference, the NCI supported the development of a Quality of Life Research supplement that focuses on describing the methods of item response theory (IRT) and its applications, as well as challenges for improving PRO measures such as pain, fatigue, physical function, and emotional distress.

The underlying reason for the need of such a resource is because many existing health outcomes instruments are cumbersome for respondents, burdensome for clinical care sites, not applicable over the continuum of care or in a variety of research settings, suffer from floor and ceiling effects, and/or lack a standardized scoring metric to allow comparisons across different health conditions. As described in the supplement, IRT provides a powerful framework to address these limitations and to build instruments that are more efficient, reliable, and valid measures of health-related quality of life (HRQOL).

Co-edited by Drs. Bryce B. Reeve (NCI), Ron D. Hays (UCLA School of Medicine), and Chih-Hung Chang (Northwestern University), the supplement was published in summer 2007 and includes the following articles:

• Applying Item Response Theory to Enhance Health Outcomes Assessment (preface)
• Applying Item Response Theory (IRT) Modeling to Questionnaire Development, Evaluation, and Refinement
• The Role of the Bifactor Model in Resolving Dimensionality Issues in Health Outcomes Measures
• Differential Item Functioning and Health Assessment
• Evaluating Measurement Equivalence Using the Item Response Theory Log-likelihood Ratio (IRTLR) Method to Assess Differential Item Functioning (DIF): Applications (with illustrations) to Measures of Physical Functioning Ability and General Distress
• A comparison of three sets of criteria for determining the presence of differential item functioning using ordinal logistic regression
• Linking Scores from Multiple Health Outcome Instruments
• Developing Tailored Instruments: Item Banking and Computerized Adaptive Assessment
• Methodological issues for building item banks and computerized adaptive scales
• IRT Health Outcomes Data Analysis Project: An Overview and Summary
• The Future of Outcomes Measurement: Item Banking, Tailored Short-Forms, and Computerized Adaptive Assessment
• Development and Evaluation of a Computer Adaptive Test for 'Anxiety' (Anxiety-CAT)
• Patient-Reported Outcomes with Innovative Technologies
• Practical and Philosophical issues surrounding a national item bank: If we build it will they come?
• Enhancing Measurement in Health Outcomes Research Supported by the U.S. Department of Health and Human Services
• Applying Item Response Theory and Computer Adaptive Testing: the challenges for health outcomes assessment
• Next Steps for Use of Item Response Theory in the Assessment of Health Outcomes