Bayesian Transition Analysis with Markov Chain Monte Carlo R package baytaAAR version 1.0.3 Provides Bayesian age estimation for bioarchaeological skeletal data using ordinal probit regression models implemented in 'JAGS' and 'NIMBLE'. The package is designed to handle multiple ordinal traits of adult individuals and incorporates a Gompertz prior on age to reflect population-level mortality. It accounts for estimation uncertainties and supports full customization of model parameters and Markov Chain Monte Carlo settings. For more details see Müller-Scheeßel et al. (2026) <doi:10.1002/ajpa.70289>. Software Depends: R (>= 4.1.0), nimble Imports: tidyr, Rdpack, dplyr, scoringRules, ggpubr, flexsurv, coda, checkmate, stats Suggests: testthat (>= 3.0.0), withr, knitr, rmarkdown, ggplot2, gridExtra, bayesplot, tidybayes, rjags, runjags, ggridges Nils Müller-Scheeßel <nils.mueller-scheessel@ufg.uni-kiel.de> Comprehensive R Archive Network (CRAN) Nils Müller-Scheeßel [aut, cre, cph] (ORCID: <https://orcid.org/0000-0001-7992-8722>), Christoph Rinne [aut] (ORCID: <https://orcid.org/0000-0002-9829-6182>) GPL-3 2026-06-15 application/tgz https://CRAN.R-project.org/package=baytaAAR doi:10.32614/CRAN.package.baytaAAR