“Which side are you on?” A historical study of union membership composition in seven Western countries

This study uses surveys from the past 60 years to study union membership in Denmark, France, West Germany, Italy, Sweden, the United Kingdom, and the United States. We first revisit aggregate union densities finding that, for France and Italy, they were at times under- and overestimated, respectively. Second, we document the evolution of the composition of union membership in terms of gender, occupation, education, and sector. Different stylized facts emerge for different groups of countries. These facts do not lend support to the composition-based theory that attributes deunionization to deindustrialization, nor to the technological theory that predicts the exit of the high-skilled from unions.