This paper employs unit root tests that allow for two endogenously determined structural breaks to study whether or not invention activities are converging across US regions/states. Using US patent data from 1929 to 1997, we find technological β-convergence in six of the nine Census regions, in...

This paper employs unit root tests that allow for two endogenously determined structural breaks to study whether or not invention activities are converging across U.S. regions/states. Using U.S. patent data from 1929 to 1997, we find technological beta convergence in six of the nine Census...