Unions and the Great Leveling: Evidence from Across the Atlantic

We investigate the role of unionization in shaping income distributions during the Great Leveling, comparing Sweden and the United States—two countries with markedly different union traditions and levels of organization. Using data from the 1940 and 1950 U.S. censuses and Swedish tax registers, we exploit plausibly exogenous variation in unionization and estimate distributional effects using quantile regressions and interactions with worker characteristics. Our results indicate that stronger unions elevated earnings in both countries, but the elasticity was roughly double in the United States compared with Sweden. U.S. unions also had a more radical impact on the earnings distribution: the effect at the 10th percentile was almost twice that at the 90th percentile while also reducing earnings differences between workers with different levels of skill and education. We relate the difference between the two countries to their patterns of union membership: in the United States, it was concentrated among lower-skilled workers, whereas in Sweden it was high across the occupational distribution and among employees with both low and high levels of education, shaping their incentives to negotiate higher wages and compress the earnings distribution. Our study shows that unions played a pivotal role in the Great Leveling in two countries at opposite ends of the labor-market-regime continuum. While there appears to be a trade-off between unions’ organizational reach and impact on wages, Sweden’s more encompassing unions have been more successful in engendering a compressed income distribution. U.S. unions have instead gradually lost their power to affect outcomes.