st: Brant test interpretation with categorical variables

[Massimiliano Volpi <maxvolpi@hotmail.com>]

Dear Statalisters,

I would like to ask for your help in  the interpretation of the results from Brant test (SPost, Scott Long).
I am using a number of categorical variables that I expand into dummy variables with the command xi. I have tested my model with Brant and it tipically turns out that only one of the dummies within each categorical variable (which in my case represent the importance of motivations: irrelevant, of little importance, important, etc) violates the assumption of parallel lines.
So, I would like to ask whether you would suggest to do a LR test to check whether all the dummies within the same categorical variable simultaneously violate the assumption or whether just one "sub-category" (a single dummy value) is enough to consider the hypothesis to be violated (of course the question only makes sense if the LR test does not reject the parallel line assumption for all the dummies in the same category).
It is probably more an econometric question than just one about Stata, but I am getting confused.
Thanks.

Best Wishes

Max Volpi
Swindon, UK
 		 	   		  
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