GNU R assessment of regression models performance

 Utilities for computing measures to assess model quality,
 which are not directly provided by R's 'base' or 'stats' packages. These
 include e.g. measures like r-squared, intraclass correlation coefficient
 (Nakagawa, Johnson & Schielzeth (2017) <doi:10.1098/rsif.2017.0213>),
 root mean squared error or functions to check models for overdispersion,
 singularity or zero-inflation and more. Functions apply to a large variety of
 regression models, including generalized linear models, mixed effects models
 and Bayesian models.