Hi Listers,

I want to make sure I am correctly interpreting my 2*3 interaction following a logistic regression. My predictors are sex (m vs. f) and task type (easy vs. medium vs. high) on completion rates (yes/no).

I find including the interaction term in my model does improve the fit using a likelihood ratio test so I would like to know what is going on. Male and easy are the reference in my anlalysis category as coded as 0. logistic pass i.sex##i..task

To compare females (to males) for each test type, I use the following:

logistic pass i.sex#i..task i.task

which a colleague pointed out is equivalent to:

lincom 1.sex_n+1.sex#0.task
lincom 1.sex_n+1.sex#1.task
lincom 1.sex_n+1.sex#2.task

Is this correct?

I am unsure why, in the lincom statement, only sex and the interaction term are included but not task - any explanation would be much appreciated.

Thanks,
Laura