A recursive analysis of network and institutional evolution is offered to account for the decentralized structure of the commercial field of the life sciences. Four alternative logics of attachment-accumulative advantage, homophily, follow-the-trend, and multiconnectivity-are tested to explain the structure and dynamics of interorganizational collaboration in biotechnology. Using multiple novel methods, the authors demonstrate how different rules for affiliation shape network evolution. Commercialization strategies pursued by early corporate entrants are supplanted by universities, research institutes, venture capital, and small firms. As organizations increase their collaborative activities and diversify their ties to others, cohesive subnetworks form, characterized by multiple, independent pathways. These structural components, in turn, condition the choices and opportunities available to members of a field, thereby reinforcing an attachment logic based on differential connections to diverse partners.

W e contend that two important, nonrelational, features of formal interorganizational networks-geographic propinquity and organizational form-fundamentally alter the flow of information through a network. Within regional economies, contractual linkages among physically proximate organizations represent relatively transparent channels for information transfer because they are embedded in an ecology rich in informal and labor market transmission mechanisms. Similarly, we argue that the spillovers that result from proprietary alliances are a function of the institutional commitments and practices of members of the network. When the dominant nodes in an innovation network are committed to open regimes of information disclosure, the entire structure is characterized by less tightly monitored ties. The relative accessibility of knowledge transferred through contractual linkages to organizations determines whether innovation benefits accrue broadly to membership in a coherent network component or narrowly to centrality. We draw on novel network visualization methods and conditional fixed effects negative binomial regressions to test these arguments for human therapeutic biotechnology firms located in the Boston metropolitan area.

High triglycerides and low HDL cholesterol, but not low-density lipoprotein cholesterol, predict an increased risk of renal dysfunction. The treatment of these lipid abnormalities may decrease the incidence of early renal disease.

Industrial districts and regional clusters depend on the networks that arise from reciprocal linkages among co-located organizations, while physical proximity among firms can alter the nature of information and resource flows through networks. We consider the joint effects of geographic propinquity and network position on organizational innovation using negative binomial count models of patenting activity for U.S.-based life science firms in industrial districts and regional clusters across a 12-year time period, 1988–1999. We find evidence that regional agglomeration and network centrality exert complementary, but contingent, influences on organizational innovation. Results show that in the high-velocity, research-intensive field of biotechnology, geographic and network positions have both independent and contingent effects on organizational innovation. The influence of centrality in local, physically co-located partner networks depends on the extent to which firms are also embedded in a global network comprising physically distant partners. Such global centrality, however, alters how proximity to two important classes of organization-other biotechnology firms and public sector research organizations, such as universities, research institutes, and teaching hospitals—influences innovation. Regional agglomeration shapes the character of information and resource flows through networks, while much of what makes industrial clusters region-like involves the structure of their internal networks. We conclude that network effects persist both independently and interdependently with geographic variables, and regional characteristics influence the degree to which centrality enhances innovation.

We draw on diverse data sets to compare the institutional organization of upstream life science research across the United States and Europe. Understanding cross-national differences in the organization of innovative labor in the life sciences requires attention to the structure and evolution of biomedical networks involving public research organizations (universities, government laboratories, nonprofit research institutes, and research hospitals), science-based biotechnology firms, and multinational pharmaceutical corporations. We use network visualization methods and correspondence analyses to demonstrate that innovative research in biomedicine has its origins in regional clusters in the United States and in European nations. But the scientific and organizational composition of these regions varies in consequential ways. In the United States, public research organizations and small firms conduct R&D across multiple therapeutic areas and stages of the development process. Ties within and across these regions link small firms and diverse public institutions, contributing to the development of a robust national network. In contrast, the European story is one of regional specialization with a less diverse group of public research organizations working in a smaller number of therapeutic areas. European institutes develop local connections to small firms working on similar scientific problems, while cross-national linkages of European regional clusters typically involve large pharmaceutical corporations. We show that the roles of large and small firms differ in the United States and Europe, arguing that the greater heterogeneity of the U.S. system is based on much closer integration of basic science and clinical development.