Persistence of innovative activities, sectoral patterns of innovation and international technological specialization

In this paper, we focus on the role of persistence and heterogeneity of innovative activities at the level of the firm in determining the patterns of technological change in different industries and countries. We ask: are persistence and heterogeneity associated with higher degrees of concentration in innovative activities, stability in the ranking of innovators, and lower degrees of entry and exit in the population of innovators? Or, do the patterns of innovation depend on other variables like firm size and industrial concentration? Moreover, what are the relationships between the patterns of innovative activities, their determinants, and the technological specialization of countries? We compute indicators of persistence and heterogeneity using the OTAF-SPRU patent database at the firm level for five European countries over the period 1969–1986 for 33 technological classes. Then, we estimate the relationships between our indicators of the sectoral patterns of innovative activities and international technological specialization on the one hand, and our indicators of persistence, heterogeneity and market structure on the other. Results show that persistence and asymmetries are important (and strongly related) phenomena that affect the patterns of innovative activities across countries and sectors, while the role of market structure variables is less clear. Finally, international technological specialization is associated to a competitive core of persistent innovators.