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Re: st: predict after svy logit


From   Nick Winter <nw53@cornell.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: predict after svy logit
Date   Wed, 15 Jun 2005 13:19:19 -0400

Looking at the structure of the predict command under version 8, I think the problem is that the version 9 predict routine does not properly transform the output of _predict.

But I'm sure StataCorp will be on this quickly.

BTW, the problem affects svy: probit as well.

Best,
Nick Winter
At 01:05 PM 6/15/2005, you wrote:

At 10:42 AM 6/15/2005 -0400, Schonlau, Matthias wrote:
Dear stata listers:

In version 9, When I use predict after " svy: logit" the predicted probabilities range from roughly 0.8 to greater than 2.0. I don't understand this. When predicting in Version 8.0 (under version control) I get predictions that are credible. The survey logistic regression give the same coefficients for both version 8.0 and version 9.0 , the problem is only the prediction.
My theory, incidentally, is that there is a bug in the built-in _predict command. The reason this is my theory is because I can't see what it is doing when I -set trace on-, and I don't see any other obvious culprits. If it isn't that, then I bet there is a problem with logit_p.ado.

Incidentally one other workaround (I think) is to use mlogit or ologit instead, e.g.

svy: mlogit y x
predict temp3 temp4

temp4 is the variable you want. This seems to work ok.


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