Counting processes in cancer biology

In 1953 Nordling came up with an interesting observation concerning cancer incidence rates as a function of age: the probability (per year) of getting cancer follows a power law P\sim T^\alpha where T is the age and \alpha=6 for many cancers. Following this, in 1954 Armitage and Doll proposed a simple model explaining this power law. Their model is based on a stochastic process called the counting process. In this talk I will explain what this process is, how to calculate the time to k events of some sort, and discuss some special cases (Poisson process and some simple models of cancer).