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...

A new model of economic growth introduces the knowledge filter between new generic knowledge and economically-useful knowledge. It identifies both the formation of new ventures and the absorptive capacity of incumbent firms as the mechanisms that penetrate the knowledge filter. Recent empirical...