How Item Response Theory can Help Improve Measurement and Theory Testing in Health Psychology

Abstract

This symposium aims to showcase the benefits of Item Response Theory (IRT) for measurement and theory testing in Health Psychology. It will provide the audience with a theoretical overview of its advantages and versatility via various practical IRT applications from scale development to theory testing. Good measurement is fundamental for Health Psychology research and practice. Although IRT is often more appropriate for scale development, it is still underused in our field and many researchers are unfamiliar with its methods. As IRT is currently gaining momentum, this symposium will give the EHPS community an opportunity to better assess the benefits of IRT and discuss the research opportunities it offers. The symposium will start with a general presentation of IRT methods and their uses for scale developers compared to other techniques (C. Gibbons). An example of using Rasch scaling for improving measurement of medication adherence will be presented next (M. Kleppe). IRT as a framework for theory testing will be illustrated by a Rasch analysis of health behaviors (K. Byrka). Non-parametric IRT applications will be discussed as an alternative strategy for scale development and validation (A. Dima). The symposium will end with a discussion of the opportunities IRT offers to Health Psychology researchers (M. de Bruin).