Fun With Rate Stats

Something FUN! to look at is how each team goes about ending plate appearances from their perch on the mound. There are only six outcomes to virtually all plate appearances which broke down something like this in 2014:


GB%: 32.8%/31.3%

OFFB%: 22.9%/21.3%

K%: 19.4%/22.2%

LD%: 15.4%/14.2%

BB%: 7.1%/8.6%

IFFB%: 2.4%/2.4%

As you can imagine, each of these outcomes has a different level of preferability attached. Strikeouts are great! And so are infield fly balls! Line drives are not so great ūüė¶ We can apply¬†the league average Weighted On Base Average (wOBA) coefficients to each of these outcomes to derive an idea how a teams expected wOBA looks like based on their outcome approach. Those weights look something like this:

GB: .220

FB: .335

LD: .684

BB: .689

K/IFFB: .000

Multiply the rates by the weights and you get something like a .303 wOBA for starters and .297 for relievers. These smell pretty right and give us a good idea of how a staff or pen profiles based on their ability to get strikeouts and walk and how the trajectories of balls in play that they yield. We can do this for starters in 2014 and get something like this:

Note that we do not need to park adjust these because we’re using the league average weights and just applying that to the different rates that each team allowed. We can also do this for relievers:

Wow the Rays come out very strong on both sides of the coin here as they’re led by impressive strikeout rates and when they do allow balls in play they’re limiting line drives and grounders in favor of fly balls and pop ups. The really cool think about this is that it allows us to see how the results change as we tweak the inputs.¬†If the Rays want to go away from what they’re doing towards a more groundball oriented attack we can pull the data around to get that idea.

Anyways, just a quick hitter that exemplifies what we can do with the data that exists out there. Note that you’ll need to adjust your ball in play rates to account for walks and strikeouts as balls in play are a subset of all plate appearances. Or you could just e-mail me for the workbook and then you can just copy and paste the formulas into whatever data you’d like to look at.

Pretty impressive stuff for the Rays last year and goes to show that while their pitchers are pretty good, they’re also following a plan out there that has been crafted by some bright minds and undoubtedly features little tweaks here and there.


About Jason Hanselman

Rays fan.
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One Response to Fun With Rate Stats

  1. Pingback: Calculating xwOBA for 2014 Starters and Relievers Using PA Outcomes |

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