By now you've probably heard about the chart published in the New York Times showing how much more money you'd have today if you'd invested in the stock market only during the years Democrats held the Presidency.
(In case you haven't, the scenario is that you have $10K in 1929 to invest in stocks, and you keep this money in the market only when Republicans hold the Presidency. In this case your returns to date are a meager $11,733, but if you invest only when the Democrats hold the Presidency you'd have $300,671.)
The implication is that everyone's much better (twenty-five times better!) off financially with the Democrats holding the Presidency.
Which, of course, caused my statistical self to raise a hairy eyebrow in skepticism.
Fortunately the statistically savvy folks over at Wolfram Research were similarly interested in this bold assertion and they developed a market model using their amazing Mathematica software. Theodore Gray at Wolfram found that the assumptions that the NYT made in framing their model completely skew the results and that tremendously better gains can be made by staying in the market regardless of which party holds the Presidency—you'd have nearly $3.4 million dollars in hand by doing so.
Additionally, he found that other debatable assumptions in the NYT model have a large influence as well; things like how long before a particular party's policies actually affected the market, the year you started investing, whether you re-invested your dividends or not. Surprisingly, he also found that the NYT failed to account for inflation; doing so brings the returns down to $51K under Republicans, $25K under Democrats, and $125K under both.
So while the partisan side of me wants to shout about what a biased hack job of an article the NYT published (and why the Obama campaign should have to pay for such free advertising), in reality it's just another example of how easy it is to lie with statistics. Sadly, Mark Twain's observation that "A lie can travel halfway around the world while the truth is putting on its shoes" probably still holds true, even in this Internet Age.