Testing for the Economic Impact of the U.S. Constitution: Purchasing Power Parity across the Colonies versus across the States, 1748-1811

The U.S. Constitution removed real and monetary trade barriers between the states. By contrast, these states when they were British colonies exercised considerable real and monetary autonomy over their borders. Purchasing power parity is used to measure how much economic integration between the states was gained in the decades after the Constitution's adoption compared with what existed among the same locations during the late colonial period. The U.S. Constitution's net contribution to the economic integration of the nation is found, using this method, to be not as large as is commonly supposed.