An Event History consists of a series of events where each event has an associated time of occurrence; events mark the start or end of a spell. An episode is a sequence of spells, which is a subset of the sequence of all spells that an individual undergoes; the full set constitutes the Event History. In this paper we are concerned with rule discovery for such Event Histories. Frequently interest focuses not only on the episodes which comprise of sequences of spells but also on the spell durations. We have provided a methodology for discretising such durations which utilises phase-type distributions where the phases correspond to the discretised classes.
We also discuss how the Dempster-Shafer Theory of Evidence may be utilised to provide a methodology for inducing rules from such data when they contains partial values. These are caused by spells which are incomplete, frequently because at the current time point there are spells still in progress. Our approach is illustrated using data concerning event histories for 6994 geriatric patients.
