The knowledge bases of the world's largest pharmaceutical groups: what do patent citations to non-patent literature reveal?

This article examines the knowledge bases of the world's largest pharmaceutical groups by sales. It builds upon the concepts of knowledge specialisation and knowledge integration as the relevant dimensions along which knowledge bases can be mapped. The former is studied developing indicators of breadth. Breadth is measured by analysing the evolution of specialisation by scientific field over time. It hints at the widening range of bodies of scientific and technological knowledge relevant to firms' innovative activities. Knowledge integration is studied developing indicators of depth. Depth is measured by analysing the evolution of integration across different typologies of research. It hints at the complex, non-linear interdependencies that link the scientific and technological domains. We develop the analysis on the strength of an original database of 33,127 European Patent Office patents and 41,931 citations to 'non-patent document' (of which 19,494 were identified as scientific articles included in the ISI databases) of the 30 largest pharmaceuticals groups during the period 1990-1997. The groups studied seem to have incrementally increased the breadth of their knowledge bases, moving towards the fields proper to the new biopharmaceutical research trajectory. At the same time, some of the groups studied exhibit remarkable depth in knowledge integration in particular fields such as biotechnology, biochemical research and neurosciences.