Several researchers since have worked on defense-independent pitching stats. One, called FIP for “fielding independent pitching,” was developed by Tom Tango, co-author of Playing the Percentages in Baseball who maintains the Tango on Baseball site Tangotiger.net. Tango’s formula adds 13 times home runs to three times walks, then subtracts twice times strikeouts. The result is then divided by innings pitched.
FanGraphs.com does a couple of tweaks, first including hit batters in the walk element, then adding a constant. The constant has hovered around 3.1 in recent years and is based on subtracting league average FIP from league average ERA. It doesn’t change the order of rankings. It’s just there to give the final number a familiar ERA-like look.
...Let’s apply the formula to young White Sox ace Chris Sale: 13 times 17 home runs is 221. To that add three times (43 walks plus five HBP), or 144, for a total of 365. Subtract two times his 162 strikeouts, or 324, to leave 41. Then divide that 41 by 163 innings, and his raw FIP is 0.25. Adding the constant for results so far in 2012 leaves the 3.36 FIP listed on FanGraphs.
Is that good? Yes, very. Sale ranks fifth in the AL among pitchers with enough innings to qualify for the ERA title. He trails Hernandez (2.80), Justin Verlander (2.96), Price (3.21) and Sabathia (3.30). Jake Peavy also ranks high, eighth at 3.61.