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...

Intelligently allocating research effort and funds requires deciding whether to build on recent advances or on more established knowledge. When recent advances create superior opportunities for invention, their adoption as research inputs in the invention process promotes technological progress....

We explore the determinants of research specialization across countries and its consequences for relative wages. Using a dynamic Ricardian model we examine the effects of faster international technology diffusion and lower trade barriers on the incentive to innovate. In the absence of any...

New ideas no longer fuel economic growth the way they once did. A popular explanation for stagnation is that good ideas are harder to find, rendering slowdown inevitable. We present a simple model of the lifecycle of scientific ideas that points to changes in scientist incentives as the cause of...

In 2004, Canada changed the eligibility rules for its Scientific Research and Experimental Development (SRED) tax credit, which provides tax incentives for R&D conducted by small private firms. Difference in difference estimates show a seventeen percent increase in total R&D among eligible...

The recruitment of foreign scientists enhances US science through an expanded workforce but could also cause harm by displacing better connected domestic scientists, thereby reducing localized knowledge spillovers. We develop a model in which a sufficient condition for the absence of overall...

European countries do less research than Japan and the United States. We use a quantitative multi-country growth model to ask: (i) Why is this so? (ii) Would there be any benefit to expanding research in Europe? (iii) What would various European research promotion policies do? We find that (i)...

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 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...

The rate of university patenting increased dramatically during the 1980s. To what extent did the knowledge flow patterns associated with public sector inventions change as university administrators and faculty seemingly became more commercially oriented? Using a Herfindahl-type measure of patent...