We estimate the impact of union density on wages using Portuguese matched employer-employee-contract data, extending Gelbach's (2016) omitted variable bias decomposition procedure to obtain the contribution of worker, firm, and job-title heterogeneity to the union wage premium. The principal...

Using representative data from the German Socio-Economic Panel (SOEP), this paper finds a statistically significant union wage premium in Germany of almost three percent, which is not simply a collective bargaining premium. Given that the union membership fee is typically about one percent of...