Stata The Stata listserver
[Date Prev][Date Next][Thread Prev][Thread Next][Date index][Thread index]

Re: st: predicting efficiency with xtfrontier


From   "Oleg Badunenko, EUV" <badunenko@uni-ffo.de>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: predicting efficiency with xtfrontier
Date   Sat, 19 Nov 2005 09:21:14 +0100

On 11/19/2005 2:54 AM, joserra coco wrote:
> Hi everybody,
>
> I was wondering if anybody could offer some guidance on two problems I
> have dealing with xtfrontier.
>
> Using panel data, I am trying to estimate technical efficiency for a
> group of firms, over 10 years. The main problem I encounter is that,
> when I predict the technical efficiency scores, I get a single value for
> each firm, instead of one value per firm per year. My understanding is
> that if I use the time varying efficiency option (tvd), these values
> should be different within firms from year to year. This is an example
> of the code I use.
>
> xtfrontier lny lnk lnl lnm , tvd iterate(26)
> predict efficiency, u
>
> Alternatively, I have also tried to include time dummies to account for
> technical progress. Same situation.
>
> I would appreciate any guidance on this matter. Also, once I reach the
> technical scores, I would like to make them dependent on a set of firm
> attributes (not the ones I have used in the stochastic production
> frontier). Is this supposed to be a separate analysis that cannot be
> estimated through xtfrontier?.
>
> Thanks a lot for any feedback.
> Joserra.

Hi Joserra,

you should be using "predict var, te" instead of
"predict var, u" for getting technical efficiency
scores.

And it works fine:

use http://www.stata-press.com/data/r9/xtfrontier1,
clear
xtfrontier lnmachines lnworkers lnwidgets, tvd
i(id) t(t)
predict te, te
br id te

and technical efficiency is really time-varying!

Oleg

-- 
Best regards,
OLeg Badunenko,
badunenko@uni-ffo.de
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/



© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   What's new   |   Site index