Union Membership Peaks in Midlife

Using data from 68 countries on over 8 million respondents over forty years we show union membership peaks in midlife – usually around workers’ late 40s or early 50s. In doing so we extend Blanchflower’s (2007) earlier study, incorporating a further 39 countries and another decade or so of data. We also found it in every US state and the District of Columbia as well as across industries. The fact that this relationship exists in virtually every country across the world challenges a key precept in industrial relations, namely that institutions matter: they appear to matter little, at least in the case of the hump-shaped relationship between unionization and age. The union membership rates at the age peak in the United States and the United Kingdom have lowered over time, while the age at which the peak has occurred has increased in both countries. In part this is due to increasing union membership rates among those over the age of sixty-five. Declines in membership by birth cohort have lowered union density rates as the older cohorts with historically higher membership rates leave labour markets. Although we have yet to fully understand why union membership peaks in midlife we are able to examine some of the possible explanations. The findings have important implications for our understanding of trade unionism across the world.