My first reaction was: just continue using Frontier 4.1!!! It's far better than Stata!!!

For the serious reply, I quote from myself (please NOTE that things may have changed in Stata 10!): "Frontier 4.1 let you express the technical inefficiency term as a linear combination of some variables. INEXPLICABLY, Stata (just-updated, Intercooled, version 9.2) let you do this only for the cross-sectional command -frontier-, but not for the panel counterpart -xtfrontier-. In the latter command, the inefficiency term can be only a random variable with truncated-normal distribution, or a random variable with truncated-normal distribution multiplied by a specific function of time (exponential decay)"

Nicola

P.S. I'll NOT receive/read any email but the Digest.

At 02.33 20/11/2008 -0500, you wrote:

>Dear Statalist Members,

>

>I have an unbalanced panel data set at hand and want to estimate

>agricultural production functions. In Frontier 4.1 there is the

>possibility to specify the explanatory variabels and variables

>explaining unit specific reasons for inefficiency separately. Does

>some porcedure exist in Stata to obatain the parameters of an

>inefficiency model with Stata?

>

>Every comment is appreciated.

>

>Christian BĂ¶ber

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