A Note on an R^2 Measure for Fixed Effects in the Generalized Linear Mixed Model

TL;DR

This paper proposes a new R^2 measure for generalized linear mixed models using the likelihood ratio test to evaluate the association between outcomes and fixed effects.

Contribution

It introduces a model R^2 based on the LRT statistic for assessing fixed effects in GLMMs, filling a gap in model evaluation tools.

Findings

The R^2 effectively quantifies fixed effects in GLMMs.

The measure compares full and null models using LRT.

It provides a straightforward interpretation of fixed effects strength.

Abstract

Using the LRT statistic, a model R^2 is proposed for the generalized linear mixed model for assessing the association between the correlated outcomes and fixed effects. The R^2 compares the full model to a null model with all fixed effects deleted.