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logistic regression: wls and unbalanced samples

On Apr 27, 2011, at 00:22 , Andre Guimaraes wrote:

            
??

If the proportion of 1 in the population is about 7%, how exactly is the sample "unbalanced". I don't see a reason to use weights at all if the sample is representative of the population. The opposite situation, where the sample is balanced (e.g. case-control), the population not, and you are interested in the population values, _that_ might require weighting, with some care because case weighting and sample weighting are two different things so the s.e. will be wrong. That sort of stuff handled by the survey package. 

However what you seem to be doing is to create results for an artificial 50/50 population, then project back to the population you were sampling from all along. I don't think this makes sense at all.