Re: st: Using mlogit estimates

["Tonya Cropper" <tonya_cropper@ksgphd.harvard.edu>]

Thanks Kevin and Christian for your response.  However, the ouput from a 
mlogit output is a little different.  Below, I show the estimates from the 
two possible outcomes (0 and 2, where 1 is the omitted comparison group).  I 
need to reference the variables (1 thru 6, and constant) separately for each 
output possibilities (0 and 2).  In a normal matrix, I can reference the 
elements of the matrix by the matrix name and the row and column.,  I do not 
know how to do this in Stata.  I want to be able to reference each 
coefficient separately, for example  B[2:v1] which is .10867021 .  Thanks, 
Tonya


(Outcome pred==1 is the comparison group)



. matrix B = e(b)



. matrix list B



B[1,14]

            0:          0:          0:          0:          0:          0: 
0:

           v1          v2          v3          v4          v5          v6 
_cons

y1   .09088532  -.04337326  -.71709113   .15899163   .43313382 
1.4292313   -.4900333



            2:          2:          2:          2:          2:          2: 
2:

           v1          v2          v3          v4          v5          v6 
_cons

y1   .10867021  -.00630561  -.44842215   .21496372   .16636787 
.79510967  -.04767481



----- Original Message ----- 
From: <boudreau@MIT.EDU>
To: <tonya_cropper@ksgphd.harvard.edu>
Sent: Tuesday, May 10, 2005 11:12 AM
Subject: Fwd: st: Using mlogit estimates



> Dear Tonya:
>
> For this problem, I've used matrix commands to extract the particular 
> coefficient from the matrix:
>
>
> Here is an example in relation to the e(V) matrix, but its the same idea 
> for the e(B) matrix. I recommend looking up the matrix commands to gain 
> familiarity with how to "list" and look at the matrix and other things.
>
>                         matrix varmatrix=e(V);
>                         local alpharow=rownumb(varmatrix,"lnalpha:_cons"); 
> /*I needed to "list" the matrix to figure out what the name of the row I 
> was looking for was called*/
>                         gen 
> selnalpha=sqrt(varmatrix[`alpharow',`alpharow']) in `writeline';
>
> Kevin.
>
>
>
>
>
> > X-Sieve: CMU Sieve 2.2
> > X-Authentication-Warning: hsphsun2.harvard.edu: majordom set sender to 
> > owner-statalist@hsphsun2.harvard.edu using -f
> > From: "Tonya Cropper" <tonya_cropper@ksgphd.harvard.edu>
> > To: "Statalist" <statalist-digest@hsphsun2.harvard.edu>
> > Subject: st: Using mlogit estimates
> > Date: Tue, 10 May 2005 07:32:49 -0400
> > X-Mailer: Microsoft Outlook Express 6.00.2900.2180
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> >
> > Hello,
> >
> > I am trying to use the estimates from a mlogit regression output to 
> > calculate the probabilities of three outcome using different data.  When I 
> > type in "ereturn list" after the mlogit command is run, the matrix of the 
> > estimates referenced by e(b): 1x32 is listed.  Is there anyway to 
> > reference the coefficients individually to perform a calculation such as 
> > this one:
> >
> > Pr(y=2) = exp(XB2)/(1+exp(XB2)+exp(XB3))
> >
> > where XB2 and XB3 are the set of estimates for each respected outcome 
> > times its respected value.
> >
> > Thank you,
> >
> > Tonya Cropper
> > PhD Candidate in Public Policy
> > Harvard University
> > 617.493.9601
> >
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