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Re: st: -warning: variables in at() list not found in model after mfx or mfx2


From   Richard Williams <Richard.A.Williams.5@ND.edu>
To   statalist@hsphsun2.harvard.edu, statalist@hsphsun2.harvard.edu
Subject   Re: st: -warning: variables in at() list not found in model after mfx or mfx2
Date   Fri, 20 Jul 2007 12:25:07 -0500

At 10:27 AM 7/20/2007, Mirko wrote:

Both -mfx2- and ­mfx- seem to work, but both the commands return a
warning that reads:

"-warning: variables z10 ...z30 in at() list not found in model-

I checked repeatedly and those variables are (and must be) in the model.

I then wondered if there was a maximum number that could be dealt with
by the -at()- option. Playing with my model I found out that I stop to
get that warning when I have less than 10 variables in -at()-
Without a replicable example it is hard to tell. I wonder if a possible workaround would be to center your x1-x40 variables so they all had a mean of zero, e.g. using Ben Jann's -center- command, available from SSC,

center x1-x40 if !missing(y, x1-x40, z1-z30)

and then on mfx/mfx2 specify -at(zero)-.

I think this will work so long as x1 is continuous; if it isn't then you shouldn't center it.

If you try this, also try it with the set of fewer vars (where mfx/mfx2 currently work) and confirm that results are the same.


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Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
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EMAIL: Richard.A.Williams.5@ND.Edu
WWW: http://www.nd.edu/~rwilliam


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