User communities represent a unique organizing structure for the exchange of ideas and knowledge. They are organizations composed primarily of users working collaboratively, voluntarily, and with minimal oversight to freely and openly develop and exchange knowledge around a common artifact. The...

Many markets, including markets for IPOs and debt issuances, are syndicated: each winning bidder invites competitors to join its syndicate to complete production. Using repeated extensive form games, we show that collusion in syndicated markets may become easier as market concentration falls,...

"We model spatial clusters of similar firms. Our model highlights how agglomerative forces lead to localized, individual connections among firms, while interaction costs generate a defined distance over which attraction forces operate. Overlapping firm interactions yield agglomeration clusters...

We investigate how knowledge similarity between two individuals is systematically related to the likelihood that a serendipitous encounter results in knowledge production. We conduct a natural field experiment at a medical research symposium, where we exogenously varied opportunities for...