Many years ago I had taken the 5, 10 and 15 year averages of government spending and receipts as a percent of GDP for all the OECD countries and correlated against their corresponding 5, 10 and 15 year average RGDP growth rates.
It confirmed something that everybody knew;
Countries with lower taxes grow faster than countries with higher taxes.
Correlations came in around -.3.
What got me about this data is that very few Republicans, Libertarians and other varied sorts of capitalists knew of this data and would largely rely on anecdotal evidence to support capitalism as the optimal economic system. Sure, they'd use logic. Or cite the utter and dismal record of communism in the glory days of Stalin, Chairman Mao, or modern day Kim Small Jong Il. But never really went out to see, "well, what tends to happen when countries are taxed at a higher rate."
Anyway, so I updated the figures with the most recent OECD data and, well, yeah, communism still sucks. Sorry dems and libs. When you argue against the truth, well, it's uhh...kind of hard to win.