Regression Models for Ordinal Data R package ordinal version 2026.7-26 CRAN Task View: Econometrics (https://CRAN.R-project.org/view=Econometrics) CRAN Task View: MixedModels (https://CRAN.R-project.org/view=MixedModels) CRAN Task View: Psychometrics (https://CRAN.R-project.org/view=Psychometrics) Implementation of cumulative link (mixed) models also known as ordered regression models, proportional odds models, proportional hazards models for grouped survival times and ordered logit/probit/... models. Estimation is via maximum likelihood and mixed models are fitted with the Laplace approximation and adaptive Gauss-Hermite quadrature. Multiple random effect terms are allowed and they may be nested, crossed or partially nested/crossed. Restrictions of symmetry and equidistance can be imposed on the thresholds (cut-points/intercepts). Standard model methods are available (summary, anova, drop-methods, step, confint, predict etc.) in addition to profile methods and slice methods for visualizing the likelihood function and checking convergence. Software Depends: R (>= 2.13.0), stats, methods Imports: ucminf, MASS, Matrix, numDeriv, nlme Suggests: lme4, nnet, xtable, testthat (>= 0.8), tools Rune Haubo Bojesen Christensen <rune.haubo@gmail.com> Comprehensive R Archive Network (CRAN) Rune Haubo Bojesen Christensen [aut, cre] (ORCID: <https://orcid.org/0000-0002-4494-3399>) GPL (>= 2) 2026-07-27 application/tgz https://CRAN.R-project.org/package=ordinal doi:10.32614/CRAN.package.ordinal