Peanut Butter Patents Versus the New Economy: Does the Increased Rate of Patenting Signal More Invention or Just Lower Standards?
Findings of the study confirm that inventors respond to increased likelihood of success at the patent office by filing more applications, and that the surge in patenting in the U.S. in the last two decades appears to be driven to a significant extent by an increase in the underlying invention rate.
Link
http://econwpa.wustl.edu:80/eps/io/papers/0504/0504013.pdf