We also make some minor changes to steps 2 and 3. In step 2, the logit function is chosen in the classical approach mainly because the model parameter p is bounded by 0 and 1. Since, as described below, our model parameters are not bounded by 1, we have no reason to consider their logit value. Lastly, in step 3 for model comparison we use likelihood ratio tests (LRT) rather than AIC. LRTs are chosen to test one particular assumption, which is here whether the simplest model, i.e. where no model parameter depends on risk factors, is sufficient to describe the data.