Based on many measures Democrat presidents have performed better, not because of policies, but due to external factors.
A study by Princeton University economists also found that the GDP has grown about 1.7 times faster under Democrats than under Republicans. During this same period, nonfarm jobs have grown nearly 2.2 times faster, while business investment has grown twice as quickly comparatively. The report mentioned that Democratic edge stems mainly from more benign oil shocks, superior total factor productivity (TFP) performance, a more favorable international environment, and perhaps more optimistic consumer expectations about the near-term future. It should also be noted that ten of the last eleven recessions have occurred under Republican Presidents.
Further, a new analysis by Deutsche Bank shows that, over the past few decades, there’s very little difference in the performance of the economy under Democratic and Republican presidents. Alan Ruskin wrote that the average growth rate was almost the same under both administrations, and the Presidents inherit the economy shaped by their predecessor.