Dear all,

I am trying to run the stochastic frontier model based on Battese and Coelli (1995), which looks like:

sfpanel logYield logFertilizer logLabor logOxen logSeed year, model(bc95)/

The data is two-year panel data. It doesn't work rather it gives an error message "could not calculate numerical derivates .. flat or discontinuous region encountered. I used Stata version 14.

However, I run this function based on Kumbhakar (1990), it is fine!

sfpanel logYield logFertilizer logLabor logOxen logSeed, model(kumb90) rescale difficult

Does somebody know what goes wrong here? could you please help me?

Thanks in Advance!

@Asmiro

I am trying to run the stochastic frontier model based on Battese and Coelli (1995), which looks like:

sfpanel logYield logFertilizer logLabor logOxen logSeed year, model(bc95)/

The data is two-year panel data. It doesn't work rather it gives an error message "could not calculate numerical derivates .. flat or discontinuous region encountered. I used Stata version 14.

However, I run this function based on Kumbhakar (1990), it is fine!

sfpanel logYield logFertilizer logLabor logOxen logSeed, model(kumb90) rescale difficult

Does somebody know what goes wrong here? could you please help me?

Thanks in Advance!

@Asmiro

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