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Re: st: xtfrontier tvd

From   Apurba Shee <>
Subject   Re: st: xtfrontier tvd
Date   Sat, 7 May 2011 21:33:40 -0400

Hi Scott,
   Thanks for the idea. I tried rescaling the independent variables
(logindepvar - mean(logindepvar)) ... still convergence issue. any
idea of other scaling? I am getting very low technical efficiency
(around 10%) for the other sectors. Just to double check, does this
prediction command (predict te, te) give technical efficiency or
technical inefficiency?

On Fri, May 6, 2011 at 4:05 PM, Scott Merryman <> wrote:
> You can specify more than one technique so that ML will switch between
> the algorithms:
> . webuse xtfrontier1,clear
> . xtfrontier lnwidgets lnworkers lnmachines , tvd difficult tech(nr  dfp)
> In the sectors where are you having problems you might try to rescale
> the variables so that are all on about the same scale.
> Scott
> On Fri, May 6, 2011 at 1:29 PM, Apurba Shee <> wrote:
>> Hi Scott,
>> I have tried the –difficult- option that does not help. But when I use
>> other maximization technique; for bhhh it shows bhhh requires
>> observation level scores, and for dfp and bfgs it shows stepping has
>> contracted, resetting dfp/bfgs Hessian, discontinuous region
>> encountered cannot compute an improvement. I used xtfrontier lndepvar
>> lnindepvars, tvd diff technique(bhhh). Do you know how to make these
>> techniques work. I appreciate your help.
>> Apurba
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