We conduct the first empirical test of the knowledge burden hypothesis, one of several theories advanced to explain increasing team sizes in science. For identification, we exploit the collapse of the USSR as an exogenous shock to the knowledge frontier causing a sudden release of previously...

We conduct the first empirical test of the knowledge burden hypothesis, one of several theories advanced to explain increasing team sizes in science. For identification, we exploit the collapse of the USSR as an exogenous shock to the knowledge frontier causing a sudden release of previously...

The growing peer effects literature pays particular attention to the role of stars. We decompose the causal effect of hiring a star in terms of the productivity impact on: 1) co-located incumbents and 2) new recruits. Using longitudinal university department-level data we report that hiring a...

We report a puzzling pair of facts concerning the organization of science. The concentration of research output is declining at the department level but increasing at the individual level. For example, in evolutionary biology, over the period 1980 to 2000, the fraction of citation-weighted...

"We examine how the spatial and social proximity of inventors affects knowledge flows, focusing especially on how the two forms of proximity interact. We develop a knowledge flow production function (KFPF) as a flexible tool for modeling access to knowledge and show that the optimal spatial...