1. An apparatus, comprising: processing circuitry; and logic, at least partially implemented by the processing circuitry, the logic to: obtain medical event history information for subjects, the medical event history information comprising medical history events; determine a particular medical event to determine a probability of occurrence based on a presence or absence of medical history events at specific prior time periods; select, at random, one medical event per subject for subjects having experienced the particular medical event for inclusion in a set of medical history events to be modeled; select, at random, one medical event per subject for subjects having not experienced the particular medical event for inclusion in the set of medical history events to be modeled, each of the medical events selected for subjects having not experienced the particular medical event having a same seasonality as the medical events selected for subject having experienced the particular medical event; generate a model based on the set medical history events for subjects having experienced the particular medical event and having not experienced the particular medical event, the model comprising a decision tree having nodes corresponding with medical history events from the set of medical events, each of the nodes having an indication of a probability of occurrence for the particular medical event based on whether the corresponding medical history event of the node occurred or did not occur within a specific time period; and present the decision tree having the nodes on a display.