Comparing Public and Private Schools: The Puzzling Role of Selectivity Bias
解释了为何使用相同数据和类似估计方法的研究，对公立与天主教学校相对教育质量的结论存在冲突，并澄清了控制选择性偏差的两步法的假设与风险，同时展示了检测选择性偏差的替代方法。
Recent articles using the same data and variants of the same estimation technique report conflicting estimates of the relative quality of education provided by public and Catholic schools. This article explains the reasons for the conflict. In so doing, the article clarifies the assumptions underlying the increasingly popular two-step methods for controlling selectivity bias and highlights the hazards of using these methods when the assumptions are not satisfied. The article also illustrates an alternative method for detecting the presence of selectivity bias.