Understand the limitations of the modeling of survival data, especially as pertains to the Cox proportional hazards model.An introduction to model-free estimates of survival, namely, the restricted mean survival time/restricted mean lost time.Use R (The R Foundation for Statistical Computing, Austria) or STATA® (The STATACorp, College Station, TX, USA) to perform analyses and obtain these parameters from a dataset., Supplementary Information: The online version contains supplementary material available at 10.1007/s12055-021-01167-4., Competing Interests: Conflict of interestThe authors declare no competing interests., (© This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply 2021.)