ABSTRACT
An important type of discrete data occurs when we model the duration to some pre-specified event. Examples of such data include: the duration in unemployment from the start of a spell of unemployment until the start of work, the time between shopping trips or the time to first marriage. This type of discrete data has several important features such as left and right censoring, time-varying explanatory variables and competing risks. We will examine each of these features in the following sub-sections.
