I started at Eisenhower in 1953 because the data series itself starts abruptly in the middle of Truman's term. More over, as inaguration starts a thrid of the way into first quarter, I have adopted the convention of counting first quarters under the previous president--this is certainly the most reasonable option, since it takes time for presidents to start enacting their own policies. Also, I used Real GDP instead of Real GDP per Capita because the latter preferred series only starts in 1960. This substitution is valid if (as I suspect is true) population growth is uncorrelated with presidential parties. What the figure shows is that every democrat has outperformed every republican with two exceptions:
- Reagan actually managed to do a little better than Carter, and
- Obama, dealing with the recovery from the worst recession by far in this series, has done worse than everyone.
But, just remember that looking at this data and claiming that Republicans are actually better for the economy is a pretty extraordinary claim that requires extraordinary evidence. There were 6 republican presidents and 5 democrats. 5 out 6 republicans beat only 1 out of 5 democrats. And that 6th republican hardly did any better, beating only 2 out of 5 democrats.