The article tries to answer an old question of economic theory and institutional economics: How do trade unions fit into a market economy? Are they a constitutive element of the market order or: are they a source of irritation and disruption?

In this note, we apply a new test by Lind and Mehlum (2010), casting doubt on the claim proposed by Blanchflower (2007) that the probability of unionisation follows an inverted U-shaped pattern in age with a maximum in the mid- to late 40s. With this new test for an inverted U-shaped pattern,...