We develop and test four alternative logics of attachment – accumulative advantage, homophily, follow-the-trend, and multiconnectivity – to account for both the structure and dynamics of interorganizational collaboration in the field of biotechnology. The commercial field of the life sciences is typified by wide dispersion in the sources of basic knowledge and rapid development of the underlying science, fostering collaboration among a broad range of institutionally diverse actors. We map the network dynamics of the field over the period 1988-99. Using multiple novel methods, including analysis of network degree distributions, network visualizations, and multi-probability models to estimate dyadic attachments, we demonstrate how different rules for affiliation shape network evolution.
Commercialization strategies pursued by early corporate entrants are supplanted by collaborative activities influenced more by universities, research institutes, venture capital, and small firms. As organizations increase both the number of activities on which they collaborate
and the diversity of organizations with whom they are linked, cohesive subnetworks form that are 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 connections to diverse partners that are differently linked. The dual analysis of network and institutional evolution provides an explanation for the decentralized structure of this science-based field.