What are we trying to learn?

Choose whose effect matters, compare absolute and relative risks, and feel the difference between a survival gap and an area. Then ask what the observed data can tell you about that question.

Further reading: The targeted learning roadmap; ICH E9(R1): defining an estimand; Royston and Parmar: restricted mean survival time. Numerical values are generated by the accompanying scientific kernels; these finite examples illustrate the theory under the assumptions stated beside each experiment.