Dear FS experts, 

Sorry for my confusion here, but I'm wondering why dichotomous nuisance variables (e.g., gender) can't be used in qdec? I was thinking that if it uses a generalized linear model then it should be ok? I read other posts and understand why discrete factors can't be used with more than 2 levels, but was thinking that dichotomous variables should be different.  

NB. we're trying to run a simple two group comparison, but we two dichotomous variables that we want to control for. 

Many thanks for your help, 

Dom