st: xtsur and Biorn (2004)

[Alper.Demirdogen@ankara.edu.tr]

Hello

I?m a PhD student at Agricultural Economics Department of Ankara University. I want to analyze agricultural
support effect on acreage level as a part of my thesis. In this context, I want to learn Biorn?s
method (2004) http://www.sciencedirect.com/science/article/pii/S0304407603002768. I have very simple problem
with this method.

There is user-written STATA code for this method (xtsur). My results and xtsur?s results couldn?t match. I
figured it out that there was a problem in co(variation) matrix of residuals. My matrix and
xtsur?s matrix are not the same. There is a very basic example in this attachment
(http://www.alperdemirdogen.com/wp-content/uploads/biorn-example.xlsx).

If you could have few minutes and look at it, I would be greatly appreciated.


Thanks in advance
Best Regards

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