# Preface

The first edition of this book was published 1i 2012, nine years ago. Since then the field has grown and developed rapidly, both in terms of available scientific data and of software development for analyzing data, not the least in the R environment. We have also seen public need of analyzing what is going on around the world, and the present (2021) state of the COVID-19 pandemic is a striking example of that.

So the time for a second edition of the book is now. The basic chapters on Cox regression and proportional hazards modeling are much the same as in the first edition, but they have been updated. There are two new chapters, Chapter 4, Explanatory Variables and Regression, and Chapter 7, Register-Based Survival Data Models. Compared to the first edition, chapters have been reordered so that the logical flow is clearer.

[some more to be added here…]

The writing of this book has been done in parallel with the development of the R package eha . All the data sets used in the examples in this book are available in eha, so you can easily play around with them on your own.

The R session information when last compiling this book is shown below:

xfun::session_info()
R version 4.0.3 (2020-10-10)
Platform: x86_64-pc-linux-gnu (64-bit)
Running under: Ubuntu 20.04.1 LTS

Locale:
LC_CTYPE=en_US.UTF-8
LC_NUMERIC=C
LC_TIME=sv_SE.UTF-8
LC_COLLATE=en_US.UTF-8
LC_MONETARY=sv_SE.UTF-8
LC_MESSAGES=en_US.UTF-8
LC_PAPER=sv_SE.UTF-8
LC_NAME=C
LC_TELEPHONE=C
LC_MEASUREMENT=sv_SE.UTF-8
LC_IDENTIFICATION=C

Package version:
base64enc_0.1.3 bookdown_0.21   compiler_4.0.3
digest_0.6.27   eha_2.8.5.9050  evaluate_0.14
glue_1.4.2      graphics_4.0.3  grDevices_4.0.3
grid_4.0.3      highr_0.8       htmltools_0.5.1
jsonlite_1.7.2  knitr_1.30      lattice_0.20-41
magrittr_2.0.1  markdown_1.1    Matrix_1.3-2
methods_4.0.3   mime_0.9        rlang_0.4.10
rmarkdown_2.6   rstudioapi_0.13 splines_4.0.3
stats_4.0.3     stringi_1.5.3   stringr_1.4.0
survival_3.2-7  tinytex_0.28    tools_4.0.3
utils_4.0.3     xfun_0.20       yaml_2.2.1