The significant decline in union membership since the early 1970s explains approximately 20% of the rising hourly wage inequality among women and about one-third among men, according to a new study in the American Sociological Review.
"Our study underscores the role of unions as an equalizing force in the labor market," co-author Bruce Western, a professor of sociology at Harvard University, told Science Daily. "Most researchers studying wage inequality have focused on the effects of educational stratification - pay differences based on level of education - and have generally under-emphasized the impact of unions."
Looking primarily at full-time, private-sector workers, the study found that the decline in a unionized labor force explains about 33% percent of the rise in wage inequality among men. Among women, de-unionization explains about 20%.