The evolution of collective strategies among organizations

Many organizations are made up of other organizations that have decided to act collectively - as with research and development consortia, industrial a lliances, trade associations, and formal political coalitions. These collec tive organizations can be characterized by their differing strategies: some are general in scope, while others specialize on a more narrow purpose. Wh at explains the prevalence of generalism and specialism among collective or ganizations? We develop an ecological model in which collective organizatio ns compete over member organizations. Assuming that an organization joins a collective when its objectives match that of thr collective, our model pre dicts a generalism bias in the ecology of founding and growth among collect ive organizations. This outcome is predicted to be path dependent, however, emerging over time according to relatively minor differences in initial co nditions. These predictions are supported in an analysis of founding and gr owth rates among US R&D consortia, and the model helps to account for the n umbers, sizes, and strategic diversity of these consortia.