This paper presenta a general equilibrium model of imperfect competition in which firm efficiency depends on the level of product market competition. X-efficiency is shown to arise to the extent unions directly affect the level of employment. A positive relationship is established between total...

In this paper a theoretical framework is provided to link firm efficiency to product market competition. In particular x-efficienct is shown to arise to the extent unions directly affect the level of employment. A positive relationship is established between social efficiency and x-efficiency,...