PROC LOGISTIC: what is the requirement of minimal number of responders in binary logistic regression

[jcpenny2002]

This is an empirical question. To develop a binary logistic regression model, what is the requirement of minimal number of responders (if the dependent variable is responders /nonresponders)?

[SteveDenham]

First off, the dependent variable ought to be better represented as responders/(responders + nonresponders), otherwise you could get a ratio larger than one, which would not fit into logistic regression.

Once you get that going, I think I have seen a rule of thumb of 10 responders per independent variable estimated in the model.  Should be a good starting place.

Steve Denham