This appendix was written in July 2020 and extended in December 2020. The accompanying paper was published in July 2021.
Following that publication, I added a postscript describing what I would do differently if I would report on a similar analysis in the future. I also updated the references to the (now published) paper in the appendix.
(The December 2020 version was deleted by mistake and reuploaded in July 2021).
This appendix accompanies the following paper:
de Graaf, H., ter Schure, J., & van Liere, G. A. (2022). How old are young people when they start having sex? Unravelling the applicability of Cox proportional hazards regression. Journal of Public Health, 30(8), 1873-1880.