Concentration, Unionism, and Labor Earnings: A Sample Selection Approach
使用工资与工会会员的联立方程模型，估计市场集中度对工资的弹性约为0.2，发现集中度主要通过工会化间接影响工资。
Using a simultaneous equations model of wages and union membership, the elasticity of the wage with respect to market concentration is estimated to be approximately 0.2. The estimate uses a large data set and extensive controls to measure concentration's direct effect on the wage, an indirect effect through unionization, and a feedback effect. The indirect effect represents the majority of concentration's effect. Copyright 1988 by MIT Press.