The impact of market structure on environmental efficiency in the United States: A quantile approach
研究了美国各州工业设施的环境效率与市场集中度之间的关系，发现全球金融危机后两者关系发生变化，且在不同效率水平上呈现非线性特征。
Abstract This paper investigates the relationship between efficiency and market structure for a sample of industrial facilities dispersed among the U.S. states. In order to measure the relevant efficiency scores, we use a data envelopment analysis allowing for the inclusion of desirable and undesirable (toxic chemical releases) outputs in the production function. In the next stage, we utilize the bootstrapped quantile regression methodology to uncover possible nonlinear relationships between efficiency and competition at the mean and at various quantiles before and after the global financial crisis (2002 and 2012). In this way, we impose no functional form constraints on parameter values over the conditional distribution of the dependent variable (efficiency). At the same time, we estimate at which part of its cumulative distribution function the efficiency is located and draw substantial conclusions about the range of policy measures obtained. The empirical findings indicate that the relationship between efficiency and market concentration did change in the aftermath of the global financial crisis. The empirical results survived robustness checks under the inclusion of an alternative market concentration indicator (CR8).