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st: RE: mlogit, mfx2, predict and a bug?
First, if I am puzzled by a result than that most often
indicates a bug in my thinking and not a bug in Stata (note
only a capital S). You are using programs that aren't part
of official Stata (-outreg2- and -mfx2-), please tell us
where you got them from. All these points are in the
Statalist FAQ (see bottom of each statalist post). The
statalist FAQ does not exist to make your live on statalist
more difficult but to help you ask questions that are more
likely to get an answer.
Second, you'll have to be more concrete that that. Put
yourself into the position of someone that tries to answer
your question. That person would want to reproduce your
results, understand why you find those results puzzling
and see what Stata is doing at each step. Try to fill in
the example below so that it shows the results that
puzzled you.
*------------ begin example -----------
set more off
sysuse auto, clear
recode rep78 1/2 = 3
mlogit rep78 price mpg foreign
mfx2
predict pr2*
mlogit rep78 price mpg foreign
predict pr*
*--------------- end example ----------
(For more on how to use examples I sent to the Statalist, see
http://home.fsw.vu.nl/m.buis/stata/exampleFAQ.html )
-----------------------------------------
Maarten L. Buis
Department of Social Research Methodology
Vrije Universiteit Amsterdam
Boelelaan 1081
1081 HV Amsterdam
The Netherlands
visiting address:
Buitenveldertselaan 3 (Metropolitan), room Z434
+31 20 5986715
http://home.fsw.vu.nl/m.buis/
-----------------------------------------
-----Original Message-----
From: [email protected] [mailto:[email protected]]On Behalf Of Stephan Brunow
Sent: donderdag 7 juni 2007 11:35
To: [email protected]
Subject: st: mlogit, mfx2, predict and a bug?
Dear Statalisters,
there might be a bug in STATA.
Here is what we did in short:
.mlogit...
.outreg2...
.mfx2...
.predict (probabilities of all choices)
Then we looked for the maximum of the choice probabilities to get a
hypothetical choice and tabulate it with the true choice. Obviously, some of
our categogies did not get chosen by the model at all.
However, if we do
.mlogit
.predict (probabilities of all choices)
And do the same thing to compare modeled maximum choice and true choice, weg
et a <normal> result where all choices are met to some extend.
Is there a bug or what might be the reason?!
Stephan
*
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*
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