Explanatory item response models for continuous data: A tutorial in R
Abstract
The explanatory item response model (EIRM) is a common tool in psychometrics to model person and item characteristics as functions of covariates. Existing tutorials demonstrate how to model dichotomous or polytomous item responses. In this tutorial, we show how to fit the extended two-parameter logistic (E2PL) item response model for continuous item responses using the brms package in R. Using two worked examples with visual analog scale data, we demonstrate data exploration, model building, and interpretation strategies. By following this tutorial, researchers will be able to fit and interpret the EIRM for continuous item response data.
Fields of Study & Subjects
Advanced Statistical Modeling Techniques
Statistical Methods and Inference
Statistical Methods and Bayesian Inference
Publication details
- Journal / source
- Behavior Research Methods
- Publisher
- Springer Science and Business Media LLC
- Volume
- 58
- Issue
- 5
- Publication date
- 16 April 2026
- Language
- EN