Coauthorship and the Measurement of Individual Productivity

We propose a new index of individual scientific productivity that formally accounts for coauthorship, separating individual from collective productivity. In contrast to existing measures, our index, CoScore, reflects the complete coauthorship network, not only the publication record of the author being ranked. CoScore uses the varying levels of success of all academic partnerships to infer, simultaneously, an author’s productivity and her credit on each of her papers. Crucially, the productivities of all authors are determined endogenously via the solution of a fixed point problem. We show that CoScore is well defined and provide axiomatic foundations for the associated rule used to allocate credit on coauthored papers. We illustrate CoScore for a large database of papers in economics.