topic Re: class variable question in Statistical Procedures

class variable question

proctice — Fri, 02 Sep 2016 17:41:05 GMT

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.

Re: class variable question

Tom — Fri, 02 Sep 2016 17:44:55 GMT

It probably depends on what PROC you are using.

Can you show the code you used? Perhaps some of the statistics the proc generated?

Re: class variable question

proctice — Fri, 02 Sep 2016 18:59:04 GMT

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.