Re: st: Technical Efficiency with Stata sfpanel command

[Aristeidis dadoukis <a_dado12@yahoo.co.uk>]

Dear Nick,

Thank you for the comments.  I tried the exact model specifications on Frontier 4.1 and the model produced results.  This leads me to believe that I am not doing something right when using Stata.  I tried retreating to a simpler model (ie removing in turn 1 input and 1 output) as you suggested, however it still did not work on Stata.  It seems that no matter what I try in Stata the MLE does not converge.  I would really appreciate any ideas as to where I should start looking into.

Thanks and regards
Aristeidis Dadoukis    



>________________________________
> From: Nick Cox <njcoxstata@gmail.com>
>To: "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> 
>Sent: Friday, 21 February 2014, 15:09
>Subject: Re: st: Technical Efficiency with Stata sfpanel command
> 
>
>-sfpanel- is user-written, as you are asked to explain:
>
>SJ-13-4 st0315  . . . . . . . . . . . Stochastic frontier analysis using Stata
>        . . . . . . . . . . . F. Belotti, S. Daidone, G. Ilardi, and V. Atella
>        (help sfcross, sfcross_postestimation, sfpanel,
>        sfpanel_postestimation if installed)
>        Q4/13   SJ 13(4):719--758
>        estimates cross-sectional and panel-data stochastic frontier
>        models
>
>The authors may (should) have good answers, but otherwise
>
>1. Difficulties fitting a model to your data could just stem from your
>data being unsuitable for your model, and without a sight of your data
>it's difficult for anyone to comment.
>
>2. People who do this kind of thing (not me) would surely be
>interested in whether you have success with fitting this model in
>other software, which does not seem to be spelled out here.
>
>3. The usual advice if a model doesn't fit is to retreat to trying a
>simpler model, although I have no idea whether that even makes sense
>in this case.
>
>4. Regardless of whether  Battese and Coelli (1995)  is utterly
>standard in this field, you are asked to avoid minimal name (date)
>references on Statalist.
>Nick
>njcoxstata@gmail.com
>
>
>On 21 February 2014 14:53, Aristeidis dadoukis <a_dado12@yahoo.co.uk> wrote:
>> Dear Statalist members,
>>
>> I am new to Stata, so far I was using the Frontier 4.1 software.  I am interested in estimating an input oriented distance function using the Battese and Coelli (1995) model specifications, and then deriving scale efficiencies for individual banks.
>>
>> My model includes 3 inputs (x), 3 outputs(y) and 3 exogenous variables(z).  I have prepared the data for the translog function in the same way as when using the Frontier 4.1 software (ie arithmetically mean adjusting the inputs/outputs and generating the translog terms).  My sample covers  8 years and 15 obs per year.
>>
>> However, when using the sfpanel command the MLE does not converge.  The command that I used is the following (please note that I also included the translog terms in the command)
>>
>> sfpanel lnx1 lnx2 lnx3 lny1 lny2 lny3, model(bc95) emean(z1, z2, z3)
>>
>> I would appreciate any advice on what might be wrong.
>>
>> Aslo, what are the steps for estimating the scale efficiencies through Stata?
>>
>> Thanks and regards
>> Aristeidis Dadoukis
>>
>>
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