“…One reason why rational workers may join a trade union could be that members earn a higher wage than non-members. There is substantial evidence of a membership wage premium in the USA (see, for example, Budd and Na, 2000;Eren 2009;Schumacher, 1999), 1 whereas the evidence for the UK is more mixed (see, for example, Blanchflower and Bryson, 2010;Booth and Bryan, 2004;Hildreth, 2000;Koevoets, 2007). For Germany, however, the available evidence indicates no link between trade union membership and wages (Fitzenberger et al, 1999;Pannenberg, 2004, 2011a;Wagner, 1991).…”