A nonlinear mixed model framework for item response theory.

  title={A nonlinear mixed model framework for item response theory.},
  author={Frank Rijmen and Francis Tuerlinckx and Paul De Boeck and Peter Kuppens},
  journal={Psychological methods},
  volume={8 2},
Mixed models take the dependency between observations based on the same cluster into account by introducing 1 or more random effects. Common item response theory (IRT) models introduce latent person variables to model the dependence between responses of the same participant. Assuming a distribution for the latent variables, these IRT models are formally equivalent with nonlinear mixed models. It is shown how a variety of IRT models can be formulated as particular instances of nonlinear mixed… CONTINUE READING