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Re: st: RE: Using -if- when running panel-corrected OLS pooled regressions


From   "Clive Nicholas" <Clive.Nicholas@newcastle.ac.uk>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: RE: Using -if- when running panel-corrected OLS pooled regressions
Date   Mon, 24 Nov 2003 22:04:37 -0000 (GMT)

Nick,

Thanks for that. My reasoning behind using -if- was to get round the
problem of -xtpcse- failing to run because of missings, which was what
appeared to be happening. When I replaced them with zeros, it ran, but I'm
uncomfortable with the potential consequences of making those changes, for
the reasons I gave earlier.

C.

> I see no limitation on the use of -if- with -xtpcse-.
>
> If your syntax here is a guide to what you typed,
> the comma in front of -if- is incorrect.
>
> Or it may be that your way of spelling out
>
> 	if [13 indvars] ! .
>
> was incorrect.
>
> But in any case a condition of that form
> is redundant with almost all
> estimation commands. Stata automatically
> ignores observations with values missing
> on the covariates (independent variables,
> if you will).
>
> Nick
> n.j.cox@durham.ac.uk
>
> Clive Nicholas
>
>> I've tried to get round this by using -if- to take out
>> cases with missings
>> on key variables using OLS-PCSE models. I tested this using
>> just two Xs,
>> and it ran. But when trying the full model:
>>
>> -xtpcse [depvar] [50 indvars], if [13 indvars]!=.-,
>>
>> it returns an error saying that -if- isn't allowed!
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>


Yours,
CLIVE NICHOLAS,
Politics Building,
School of Geography, Politics and Sociology,
University of Newcastle-upon-Tyne,
Newcastle-upon-Tyne,
NE1 7RU,
United Kingdom.
*
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