Do Unions Affect Labor's Share of Income: Evidence Using Panel Data

There have been a number of studies analyzing the impact of unions on labor's share of income. Most have relied on either time series or cross‐section data. The purpose of this paper is to determine the impact of unions on labor's share of income in the U.S. This study adds to the understanding of this topic by developing an analytical model of imperfect competition and estimating the model using panel data for the manufacturing sector. This study finds that unions have a positive impact on labor's share of income. Specifically, this paper finds that labor's share declined 17.9 percent between 1997 and 2006 whereas, if unionization density had remained at its 1997 level, labor's share would have declined only 13.9 percent. Thus, the decline in unionization explains about 29 percent of the decline in labor's share of income. This paper is important for three reasons. First, this paper sheds light on whether social and institutional forces play an important role in determining the distribution of income between labor and capital. Second, it helps to explain recent increases in wage inequality. Third, it has implications for understanding the potential impact of legislation, such as the Employee Free Choice Act, that would make it easier for workers in the U.S. to unionize.