In Germany, trade unions and employers associations play a role not only in wage determination but also in social affairs and labour law. While the majority of firms are organized in employers associations, less than one quarter of employees are members of a trade union. Both social partners...

Surveying some recent data and the empirical literature from various disciplines, this paper attempts to shed some light on what we know and don't know about (trends in) unionization and its determinants in advanced countries. It shows that there are relatively few robust stylized facts, for...