Diverse Expertise, Peer Effects, and Research Productivity

Does diversity in idea space matter?

(with Qi Wang)

Abstract

We empirically explore whether cognitive diversity between collaborators affects peer effects and productivity in creating knowledge. We introduce a novel index to measure the cognitive distance between two researchers, based on their publication distributions and citation relations across academic journals in which they have publications. Using individual-level panel data from the Web of Science (WoS) databases of academic papers published from 1980 to 2013, we estimate the changes in productivity of the coauthors of active and eminent life scientists who passed away unexpectedly and prematurely and examine whether the impact on coauthors differs in terms of the cognitive distance. The results show that coauthors with close cognitive distance from the deceased scientist are more likely to experience a lasting decrease in research productivity for both quantity and quality measures, while cognitively distant coauthors are only negatively affected in output quantity. The findings suggest that both knowledge spillovers and skill complementarity play a role in collaborations. The loss of an irreplaceable source of ideas seems to have a more adverse impact on a scientist’s productivity than the potentially imperfect skill substitution that follows such a loss.

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