Cox Non-Proportional Hazards Model with Time-Varying Coefficients R package surtvep version 1.0.0 Fit Cox non-proportional hazards models with time-varying coefficients. Both unpenalized procedures (Newton and proximal Newton) and penalized procedures (P-splines and smoothing splines) are included using B-spline basis functions for estimating time-varying coefficients. For penalized procedures, cross validations, mAIC, TIC or GIC are implemented to select tuning parameters. Utilities for carrying out post-estimation visualization, summarization, point-wise confidence interval and hypothesis testing are also provided. For more information, see Wu et al. (2022) <doi: 10.1007/s10985-021-09544-2> and Luo et al. (2023) <doi:10.1177/09622802231181471>. Software Depends: R (>= 4.0) Imports: Rcpp, splines, ggplot2, ggpubr, stats, tibble, rlang LinkingTo: Rcpp, RcppArmadillo Suggests: knitr, rmarkdown Lingfeng Luo <lfluo@umich.edu> Comprehensive R Archive Network (CRAN) Lingfeng Luo [aut, cre], Wenbo Wu [aut], Kevin He [aut] GPL-3 2023-10-17 application/tgz https://CRAN.R-project.org/package=surtvep doi:10.32614/CRAN.package.surtvep