I put a class variable with 12 levels into a model and I got 11 parameter estimates, but one of them is 0 with zero degrees of freedom and it is not my reference level. Any idea why this happens? It doesn't happen to my class variable with 5 levels. Thank you.
Thank you. I think I figured it out. There was another categorical variable with 2 levels that when cross-tabbed with my 12 level categorical variable had lots of empty cells. Sorry to bother you.
I think this is called complete separation. I was using Proc Genmod.
It probably depends on what PROC you are using.
Can you show the code you used? Perhaps some of the statistics the proc generated?
Thank you. I think I figured it out. There was another categorical variable with 2 levels that when cross-tabbed with my 12 level categorical variable had lots of empty cells. Sorry to bother you.
I think this is called complete separation. I was using Proc Genmod.
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