Epidemiology parameter: event-free time, how to calculate?

[Tom Hsiung]

Hello,

By

ir

and

stptime

(after

stset

) I could get the incidence rate and total person-time. But how to output or compare the average event-free time?

Definition:

Average event-free time = total person-times / group number of subjects

Tom

[Tom Hsiung]

How to make the statistic inference to this variable (average event-free person-time / average person-time)?

Tom