Extension of Nakagawa & Schielzeth's R 2 GLMM to random slopes models

Summary Nakagawa & Schielzeth extended the widely used goodness‐of‐fit statistic R 2 to apply to generalized linear mixed models ( GLMM s). However, their R 2 GLMM method is restricted to models with the simplest random effects structure, known as random intercepts models. It is not applicable to another common random effects structure, random slopes models. I show that R 2 GLMM can be extended to random slopes models using a simple formula that is straightforward to implement in statistical software. This extension substantially widens the potential application of R 2 GLMM .