United we stand? Organizational groups and spinoff mortality in the context of academic entrepreneurship

We study failures between 1993 and 2017 in the complete population of 1731 English and Scottish university spinoffs founded since 1977. We borrow and expand the concept of density dependence from organizational ecology to theorize that a spinoff's propensity to fail is affected by the number of spinoffs active not only in the aggregate population but also within its parent university's portfolio. We contribute to organizational theory, demonstrating the importance of organizational groups that form within larger populations on individual organizations' propensity to fail. We contribute to literature on academic entrepreneurship showing that, for most universities, spinoff portfolio growth can lower associated spinoffs' failure rates, but that such effects need to be juxtaposed to the aggregate population's finite capacity to support an expanding number of spinoffs.