Check out this link. Or, if you are too lazy to click, here is the gist of it:

Looking for a consistently reliable indicator of postseason success? How about our Defensive Hog Index. Since we introduced the indicator last year, it has correctly identified the winner in 18 of 19 playoff games – that’s a .947 batting average for those of you keeping score at home.   If all goes according to plan, the Steelers (No. 1 in the Defensive Hog Index) will beat the Eagles (No. 2 in the Defensive Hog Index) three weeks from now in Super Bowl XLIII.

CHFF's "Defensive Hog Index" combines three metrics:  opponent's yards per rush attempt, negative pass play percentage (combination of sacks and INTs), and third-down conversions. The Steelers not only led the NFL in this index, they also led in each of the three components. Although CHFF has been ragging on the Steelers for their poor offensive statistics, playoff success seems to correlate much better with these defensive statistics.

The Ravens, not surprisingly, are no slouches, ranking No. 3 in the Defensive Hog Index.