# How to obtain AIC with conditional logistic regression using R?

I am fitting a conditional logistic regression model with 1:4 controls using R. I wish to obtain AIC from the model. How can I extract the appropriate parameters based on object m?

library(survival)
m<-clogit(cc~exp+ factor1+ factor2 + strata(stratum),data=data1)


2*length(m$coefficients)-2*(m$loglik[2])

extractAIC() seems to work too (e.g., extractAIC(m)[2]). – chl Dec 20 '10 at 14:29