Martin Feldstein has a new short paper out with some thoughts on a relatively under-researched subject: Why is Growth Better in the United States than in other Industrial Countries?
In 2015, real GDP per capita was $56,000 in the United States. On a purchasing power basis, the real GDP per capita in the same year was only $47,000 in Germany, $41,000 in France and the United Kingdom, and just $36,000 in Italy. So the official measures of real GDP clearly point to the cumulative result of higher sustained real growth rates in the United States than in the major industrial countries of Europe and Asia.
Over the very long term, this is a truism. In order for the U.S. to be that much richer, it must have experienced faster real GDP per capita growth than comparator countries. We know from figures collated by the Maddison Project that the U.S. had around half the level of GDP per capita of the UK in the early 18th century, but by 1900 it was overtaking the UK as the richest country by income per head, and has remained in that leading position for almost all the period since.
But showing higher levels of income does not necessarily mean that the U.S. growth of GDP per capita was higher than other countries over more recent periods.