Public research systems in the United States and Europe are often compared with respect to their divergent levels of involvement in the private economy. The U.S. research system, with its mix of both public and private institutions, has long played a significant role in conducting research that...

We introduce a model of proportional growth to explain the distribution Pg(g) of business-firm growth rates. The model predicts that Pg(g) is exponential in the central part and depicts an asymptotic power-law behavior in the tails with an exponent z=3. Because of data limitations, previous...