As a businessman I'm not quite sure what to make of this op-ed by Robert S. McElvaine published October 19 in The Washington Post. In brief:
Since 1928 four successful businessmen have served as president -- Herbert Hoover, Jimmy Carter, George H.W. Bush, and George W. Bush. (Harry Truman was also a businessman, but his haberdashery went bankrupt after two years.)
If you look at the performance of the economy starting the calendar year after they took office (so as to give their policies time to take effect), and in terms of constant (inflation-adjusted) dollars, the U.S. economy grew 0.12 percent per year under presidents who had been successful businessmen, versus 5.46 percent under the rest. Also,
... In the past 84 years, GDP has grown 7 percent per year under Democrats without business experience (FDR, JFK, LBJ, Clinton and Obama) and fallen by 0.2 percent per year under Republicans with business experience (Hoover and the two Bushes). The Dow has risen an average of 16.8 percent per year under Democrats without business experience and has fallen by 3.7 percent per year under Republicans with business experience.
To be clear, there are way too few observations here to draw sound statistical inferences. But it might be enough to make one question the seemingly reasonable idea people successful in business automatically know how to lead a national economy.