英文文献：The Impact Of Recombinant Bovine Somatotropin On Dairy Farm Profits: A Switching Regression Analysis-重组牛生长激素对奶牛场利润的影响:转换回归分析使用转换回归估计了使用重组牛生长激素(rbST)对奶牛场生产和利润的影响，并分别对使用重组牛生长激素(rbST)的奶牛场和未使用重组牛生长激素的奶牛场进行了回归
英文文献作者：Tauer, Loren W.
英文文献摘要：
Production and profit impacts from the use of recombinant Bovine Somatotropin (rbST) on dairy farms were estimated using switching regression, with separate regressions for rbST-using farms and non-rbST-using farms. To correct for potential self-selection bias, a probit adoption function was estimated and used to correct the error term in each regression equation. Farmers who use rbST were found to have more formal education and have larger dairy herds, but age was not a significant determining factor in adoption. RbST was estimated to increase milk production per cow even when correcting for the fact that rbST users would have higher milk production per cow without the use of rbST. However, that greater production per cow from rbST use did not translate into an estimated impact on profits per cow.

为了校正潜在的自选择偏差，我们估计了一个probit采纳函数，并用它来校正每个回归方程中的误差项。研究发现，使用rbST的农民接受过更正规的教育，拥有更大的奶畜群，但年龄并不是收养的重要决定因素。即使修正了RbST使用者在不使用RbST的情况下，其每头奶牛的产奶量也会增加这一事实，但据估计，RbST可以提高每头奶牛的产奶量。然而，使用rbST提高每头牛的产量并没有转化为对每头牛利润的估计影响。