Though the concept of innovation systems has become influential in both academia and policy-making, an analytical approach to understanding innovation systems is still lacking. In particular, there is no analytical framework to measure ‘Mode 1’ and ‘Mode 2’ knowledge production. We propose a framework based on the proximity concept. Mode 1 and Mode 2 knowledge production are characterized by collaborations with cognitive, organizational, social, institutional and geographical proximity, and distance, respectively. Using a gravity model approach we apply our framework to the case of type 2 diabetes research and provide a characterization of the global innovation system and a comparative analysis of the North American and European innovation systems. Our main results hold that although collaborative research on type 2 diabetes generally follows a logic of proximity and hence is not characterized as Mode 2, important differences and similarities exist between the North American and European innovation systems.