6. Outside groups didn’t buy the election
Crystal Ball Senior Columnist Alan Abramowitz ran a regression analysis to see what effect outside spending had on the Senate races. The correlation between the Democratic and Republican outside spending difference and the Democratic margin was .23, which is not statistically significant. In contrast, the correlation between the Democratic margin and incumbency status was a more significant .76, and the correlation between the Democratic Senate margin in 2014 and the Democratic presidential vote margin in 2012 was an even more significant .89.
In other words, partisanship in a polarized era, represented by the ’12 presidential vote margin, was by far the strongest predictor of 2014’s Senate vote. Naturally, incumbency status is also significant. But the difference between amounts of outside spending by groups affiliated with both parties has surprisingly little effect, perhaps because both sides spent so much that the money from Republicans neutralized the cash from Democrats, and vice versa.
(h/t Political Wire)