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Re: st: Inefficiency measures greater than one for frontier commands


From   Aljar Meesters <aljar.meesters@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Inefficiency measures greater than one for frontier commands
Date   Tue, 23 Apr 2013 18:54:28 +0200

Dear Reut,

The score TE = E[exp(-s * u) | e) (s = -1 in the cost model) that
Federico is referring to can be obtained via:
- predict yourVariableName, te -
Note that this will give you a score that ranges from one to infinity,
since you are estimating a cost function as far as I understand.
TE = epx(-E[s * u | e]) can be calculated by taking the exponent of
the scores that you already have.
Best,

Aljar



2013/4/23 Reut Levi <rlevi2@student.gsu.edu>:
> Thank you Federico!
>
> Do you happen to know if there is a way to predict efficiency scores in STATA, instead of inefficiency scores?
> If there is, can you please specify the command syntax?
> If there isn't, how should I go about converting the inefficiency scores predicted to represent efficiency levels?
>
> Thank you very much,
> Reut
>
> ________________________________________
> From: owner-statalist@hsphsun2.harvard.edu [owner-statalist@hsphsun2.harvard.edu] on behalf of Federico Belotti [f.belotti@gmail.com]
> Sent: Monday, April 22, 2013 5:54 AM
> To: statalist@hsphsun2.harvard.edu
> Subject: Re: st: Inefficiency measures greater than one for frontier commands
>
> Dear Reut,
>
> in the stochastic frontier framework, "inefficiency" scores ranges from 0 to infinity, while "efficiency" scores are restricted between 0 and 1 by construction since
>
> TE = exp{-E[su|e]}  following  Jondrow et al., 1982,
>   or,
> TE = E{exp(s*u)|e}  following Battese and Coelli, 1988,
>
> where s = 1 (s = -1) in the cost frontier (production frontier) case.
>
> Hope this helps.
> Federico
>
> On Apr 21, 2013, at 2:28 AM, Reut Levi wrote:
>
>> Dear Statalist members,
>>
>> I am using the xtfrontier command to estimate inefficiency levels for the U.S banking industry. My data comprised of information from the FFIEC Call Report for the year 2012. It is a large data set with over 29,000 observations. I broke it down by asset size in order to reduce the number of observation and also because the literature suggests that asset size peer group will produce more appropriate inefficiency measures. After breaking down the dataset, the average number of banks in each peer group data set is 650, with observations for 4 quarters, totaling in 2700 data points. All of my variable are in natural logs.
>>
>> I am using the xtfrontier command with the options ti and cost. I then predict the inefficiency measures using predict with the option u, but some of my inefficiency predications are greater than one. How is it possible? The manual says that the inefficiency measures are restricted to be between 0 and 1. Am I doing something wrong? Or what could explain those measures greater than 1?
>>
>> I am relatively new to STATA so please take it into consideration in your response.
>> Thank you very much,
>> Reut
>>
>>
>> *
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>
> --
> Federico Belotti, PhD
> Research Fellow
> Centre for Economics and International Studies
> University of Rome Tor Vergata
> tel/fax: +39 06 7259 5627
> e-mail: federico.belotti@uniroma2.it
> web: http://www.econometrics.it
>
>
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>
>
>
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