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Re: st: Not concave in xtfrontier


From   "Scott Merryman" <scott.merryman@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Not concave in xtfrontier
Date   Thu, 12 Jul 2007 18:08:02 -0500

I don't think your specification is appropriate for a stochastic
frontier model.  If you wish to control for firm specific effects use
-frontier- with firm dummy variables rather than first differencing.

Scott


On 7/12/07, vinish kathuria <vinish67@yahoo.com> wrote:
Thanks Scott!

If I don't suppress constant term, for few it
converges but for few it still shows - not concave.

However, the model also requires suppressing constant
term - as it is in difference!

Vinish

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