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Re: st: predicting technical efficiency after frontier command:error message


From   Caixia Zhao <cxz@stata.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: predicting technical efficiency after frontier command:error message
Date   Wed, 4 Aug 2004 17:14:31 -0500 (CDT)

It seems that is a bug. We will fix it soon.

Caixia
cxz@stata.com



On Wed, 4 Aug 2004 smerryman@kc.rr.com wrote:

> Dev,
> 
> I was able to replicate this error.  When looking at the log, the problem appears to be the call to -fron_p.Calc-
> 
> ---------------------------------------------------------------------------------------
>        log:  C:\Documents and Settings\scott.merryman\Desktop\foo.smcl
>   log type:  text
>  opened on:   4 Aug 2004, 06:57:42
> 
> . predict te,te
> ------------------------------------------------------- begin predict ---
> <snip>
> 
> ---------------------------------------------------- begin fron_p.Calc ---
> <snip>
> 
>     - else if "`e(het)'" == "uv" {
>     = else if "uv" == "uv" {
>     - tempvar xb_v sigma_v sigma_u
>     - qui _predict double `xb_u' if `cond', xb eq(lnsig2u)
>     = qui _predict double  if __000000, xb eq(lnsig2u)
> too many variables specified
>       qui gen double `sigma_u' = exp(0.5*`xb_u')
>       qui _predict double `xb_v' if `cond', xb eq(lnsig2v)
>       qui gen double `sigma_v' = exp(0.5*`xb_v')
>       }
>       }
> 
> 
> What believe is the problem is that xb_u temporary variable is not declared before the -_predict double `xb_u' ...-
> 
> I have added xb_u to the tempvar line in -fron_p- and now it seems to work fine:
> 
> . clear
> 
> . use http://www.stata-press.com/data/r8/greene9.dta
> 
> . encode state, gen(state_id)
> 
> . qui frontier lnv lnk lnl , vhet(capital) uhet(state_id )
> 
> . predict te,te
> 
> 
> Of course, it is unwise to alter offical Stata programs; hopefully there will be an offical update to this soon.
> 
> Hope this helps,
> Scott
> 
> ----- Original Message -----
> From: Dev Vencappa <lexdvv@nottingham.ac.uk>
> Date: Wednesday, August 4, 2004 6:28 am
> Subject: st: predicting technical efficiency after frontier command:	error message
> 
> > >>
> > >>
> > Stata users,
> > 
> > I am running the following command.
> >  
> > 
> >   reg lnrev lntoen lncap lntech lndebt
> >   mat X=e(b)
> >   local a=el(X,1,1)
> >  local b=el(X,1,2)
> >  local c=el(X,1,3)
> >  local d=el(X,1,4)
> > frontier lnrev lntoen lncap lntech lndebt, diff  uhet(lnass dumfra-
> > dumother,noconstant)  vhet(lnass dumfra-dumother,noconstant) /*
> > */from(lntoen=`a'  lncap=`b' lntech=`c' lndebt=`d')
> > predict CDrev1,te
> > 
> > I am getting my parameter estimates and everything else fine, 
> > except for the predict command which gives the following error 
> > message.
> > "  too many variables specified
> >       r(103); "
> > 
> > I am basically modelling heteroscedasticity in both the one-sided 
> > and two-sided error component. In contrast, when I model 
> > heteroscedasticity in either one of them, then the predict command 
> > works fine. I have read the manual and it does not say anything 
> > about possible problems with predict, te when heteroscedasticity 
> > is modelled for both error components.
> >   Any explanation why this is happening?
> > 
> > Many thanks
> > Dev
> > 
> 
> 
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