Analysis of Event Data with Two Time Scales R package TwoTimeScales version 1.2.1 Analyse time to event data with two time scales by estimating a smooth hazard that varies over two time scales. If covariates are available, estimate a proportional hazards model with such a two-dimensional baseline hazard. Functions are provided to prepare the raw data for estimation, to fit the model and to plot the two-dimensional smooth hazard. Extension to a competing risks model are implemented. For details about the method please refer to Carollo et al. (2025) <doi:10.1002/sim.10297>. Software Depends: R (>= 3.5.0) Imports: colorspace, Epi, fields, JOPS, LMMsolver, popEpi, reshape2, spam, ucminf, viridis Suggests: knitr, rmarkdown, spelling, testthat (>= 3.0.0) Angela Carollo <carollo@demogr.mpg.de> Comprehensive R Archive Network (CRAN) Angela Carollo [aut, cre, cph] (ORCID: <https://orcid.org/0000-0002-5625-6553>), Paul H.C. Eilers [aut], Jutta Gampe [aut] GPL-3 2026-03-30 application/tgz https://CRAN.R-project.org/package=TwoTimeScales doi:10.32614/CRAN.package.TwoTimeScales en-US