Environmental Regulation and U.S. State-Level Production
利用1977-1986年美国数据，用参数和非参数方法估计环境政策对州级产出的影响，发现两者缺乏关系这一结论相当稳健。
Using data from the U.S. over the period 1977 - 1986, we estimate the impact of environmental policy on state-level output using both parametric and nonparametric techniques. We find that while the added flexibility of the nonparametric approach yields much insight, the lack of a relationship between environmental regulation and output is quite robust.