Using the same data, if I ran fit2 <-glm(formula=AR~Age+LumA+LumB+HER2+Basal+Normal,family=binomial,data=RacComp1)summary(fit2)exp(coef(fit2)) I obtained: > exp(coef(fit2))(Intercept) Age LumA LumB HER2 > Basal Normal 0.24866935 1.00433781 0.10639937 0.31614001 > 0.08220685 20.25180956 NA while if I ran
fit2 <-glm(formula=AR~Age+LumA+LumB+Basal+Normal+HER2,family=binomial,data=RacComp1)summary(fit2)exp(coef(fit2)) I obtained: > exp(coef(fit2)) (Intercept) Age LumA LumB > Basal Normal HER2 0.02044232 1.00433781 1.29428846 > 3.84566516 246.35185956 12.16443690 NA Essentially they're the same model - I just moved HER2 to the last. But the OR changed significantly. Can someone explain? For the latter result, I don't even know how to interpret as all factors have OR>1 (except Intercept), how could that possible? Can I eliminate the effect of intercept? Also, I cannot obtain OR for the last factor due to collinearity. However, I know others obtained OR for all factors for the same dataset. Can someone tell me how to obtain OR for all factors? All factors are categorical variables (i.e., 0 or 1). Thanks! Peter [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.