# Offset in Logistic regression: what are the typical use cases?

Offset is commonly used in Poisson regression to take into account different exposure (different time periods for instance): offset = log of exposure

Question: what's the typical use case of offset in logistic regression?

I assume we can't do exposure (proportional effect) in classification problems since E(y|x) can't go beyond 1 so I'm curious about why someone would need to use offset in a logisic regression.

• Why "use cases" and not "examples"? – Frank Harrell Apr 8 '17 at 15:14