Some observers would contend that conflict — latent or manifest —is the essence of industrial relations or at least most would agree that it is a deeply-rooted, enduring and essential feature of the employment relationship. Despite their partial nature, strikes are frequently used in comparative studies as an index of conflict for which statistical data are readily available. A general link has been postulated between the nature of the industrialisation process and patterns of worker protest and reaction as manifested in strike action. The work of Shorter and Tilly for France is particularly notable for its emphasis on the organisational and political positions of labour as factors influencing the level of strike activity. Few aspects of strike activity have received greater attention than the relationship between changing economic conditions and changes in the frequency of strikes. It is hardly surprising that some of the evidence from quantitative, empirical strike studies is conflicting.