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CEP Discussion Paper
Factors of Convergence and Divergence in Union Membership
Stephen Machin
November 2002
Paper No' CEPDP0554:
Full Paper (pdf)

This paper considers to what extent union decline in Britain has been characterised by convergence or divergence in union membership rates for people with different personal and job characteristics. It compares data on individual union membership in 1975, from a period when union membership was high and growing, to data in 2001 data when it is low and has been falling for over twenty years. Some factors of both convergence and divergence are identified. The clearest individual characteristic of convergence is gender. In 1975 there was a big male-female gap in union membership, whilst by 2001 one cannot reject the hypothesis that union membership rates were equal for men and women. The clearest case of divergence is age where the 1975-2001 period sees a widening of the age gap in union membership status. Other factors of convergence are the full- time/part-time status of jobs, ethnicity and workplace size. Other factors of divergence are industry and educational qualifications. Some other factors (like region) are neutral in that their relationship with union membership remains stable through time. Identification of these factors of convergence and divergence should be useful to many parties, including industrial relations scholars and union organisers. Finally, the fact that the magnitude of the relationships between union membership and a number of its determinants have shifted through time illustrates that one should be careful if one wishes to talk about empirical regularities in who is more or less likely to become a trade union member.