Re: st: Parameters returned by -lincom- after -logistic-

[Richard Williams <Richard.A.Williams.5@ND.edu>]

At 08:20 PM 5/6/2005 +0100, Roger Newson wrote:
> Hello All (especially StataCorp)
>
> I am still using Stata 8.2 under Windows 2000, and have just found out 
> about the behaviour of -lincom- if invoked after -logistic-, whereby it 
> returns in -r()- an exponentiated estimate and its asymptotic standard 
> error, even if the user has not specified any of the options -eform-, 
> -or-, -hr-, -irr- or -rrr-. (See -[R] lincom- in the Stata 8 manuals.) 
> This is a problem, because my own -lincomest- package (downloadable from 
> SSC) invokes -lincom- without any estimation options, and attempts to use 
> the estimate -r(estimate)- and its standard error -r(stderr)- to calculate 
> a 1x1 matrix of estimates and a 1x1 variance matrix to be stored in the 
> estimation results, and then lists the estimation results, using -eform()- 
> only if specified by the user. (See Newson (2003) for more about -lincomest-.)
Further, perhaps I am missing it, but I don't see anything like an xb 
option that could force the behavior you want.  I suppose you would have to 
add lines to your program to make sure it was doing what you wanted.

Another little quirk I discovered in Stata 8:  After most commands, lincom 
returns its result in r(estimate).  But, after svy commands, it returns its 
result in r(est).  This was screwing up one of my programs until I figured 
out what was going on.  I asked tech support if there was any particular 
reason for this and they said no, but they added that this would not be an 
issue in Stata 9.

I think with returns, consistency is very important.  With regular 
commands, you can often support both old and new syntax; but if you change 
the behavior/names of returns or do things inconsistently across programs 
it can create problems.


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Richard Williams, Notre Dame Dept of Sociology
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