Fixed Effects Regression Methods for Longitudinal Data Using SAS

5.6. Fixed Effects Event History Methods for Nonrepeated Events

Fixed effects Cox regression requires that at least some of the individuals in a sample experience more than one event, so that within-individual comparisons are possible. Obviously, then, the method cannot be applied to a nonrepeatable event like death. Nevertheless, under certain conditions, it may be possible to do a fixed effects analysis for nonrepeatable events by treating time as discrete and applying conditional logistic regression. In the epidemiological literature, this type of analysis is called a case-crossover study (Maclure 1991), although the implementation I describe here is a little different from the way that epidemiologists usually do it.

As usual, I begin with ...