Co-authorship and research productivity in economics: Assessing the assortative matching hypothesis

This paper estimates the relation between the size and quality of scientists' co-author networks and individual characteristics (notably productivity) in the context of institutional changes in French academia in the mid 1980s. The analysis employs the Two-Stage Residual Inclusion (2SRI) framework to handle endogeneity in individual productivity relative to the quality of co-authors. The main finding is that the size and quality of authors' networks are positively related to their productivity; this is understood as evidence of assortative matching. Other effects on co-author networks (such as life-cycles, specialties fields) are also identified. Our results have important policy implications as it indirectly demonstrates the effectiveness of career incentives linked to publication.