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SIERA and the 2009 Cardinals

February 11, 2010

This post has been modified from it’s original content, no thanks to some pesky calculation errors.

Follow the money trail! The stat de jour is SIERA, created by Matt Schwartz and Eric Seidman of Baseball Prospectus. SIERA stands for Skill-Interactive Earned Run Average, and let’s face it, See-air-ah is a lot more graceful off of the tongue than Ecks-fip. The BP writers say that SIERA accomplishes the following –

  1. Allows for the fact that a high ground-ball rate is more useful to pitchers who walk more batters, due to the potential that double plays wipe away runners.
  2. Allows for the fact that a low fly ball rate (and therefore, a low HR rate) is less useful to pitchers who strike out a lot of batters (e.g. Johan Santana’s FIP tends to be higher than his ERA because the former treats all HR the same, even though Santana’s skill set portends this bombs allowed will usually be solo shots).
  3. Allows for the fact that adding strikeouts is more useful when you don’t strike out many guys to begin with, since more runners get stranded.
  4. Allows for the fact that adding ground balls is more useful when you already allow a lot of ground balls because there are frequently runners on first.
  5. Corrects for the fact that QERA used GB/BIP instead of GB/PA (e.g. Joel Pineiro is all contact, so increasing his ground-ball rate means more ground balls than if Oliver Perez had done it, given he’s not a high contact guy).
  6. Corrects for the fact that FIP and xFIP use IP as a denominator which means that luck on balls in play changes one’s FIP.

SIERA comes out smelling like a rose when tested against other ERA estimators. In case you’re wondering, the formula for SIERA is

SIERA = 6.145 – 16.986*(SO/PA) + 11.434*(BB/PA) – 1.858((GB-FB-PU)/PA) + 7.653*((SO/PA)^2) +/- 6.664*(((GB-FB-PU)/PA)^2) + 10.130*(SO/PA)*((GB-FB-PU)/PA) – 5.195*(BB/PA)*((GB-FB-PU)/PA)
where +/- is as before such that it is a negative sign when (GB-FB-PU)/PA is positive and vice versa.

Here’s your 2009 Cardinals, by SIERA, sorted by IP.

Adam Wainwright 233 3.38 2.63 3.20 0.75 -0.18
Joel Pineiro 214 3.57 3.49 3.36 0.08 -0.20
Chris Carpenter 192.7 3.36 2.24 2.86 1.12 -0.50
Todd Wellemeyer 122.3 5.07 5.89 5.37 -0.82 0.29
Kyle Lohse 117.7 4.47 4.74 4.60 -0.27 0.14
Brad Thompson 80 4.74 4.84 4.70 -0.10 -0.04
Kyle McClellan 66.7 4.44 3.38 3.98 1.06 -0.46
Ryan Franklin 61 4.32 1.92 3.27 2.40 -1.06
Mitchell Boggs 58 4.49 4.19 4.20 0.30 -0.29
Jason Motte 56.7 3.83 4.76 4.86 -0.93 1.03
Trever Miller 43.7 2.88 2.06 3.41 0.82 0.52
Dennys Reyes 41 4.20 3.29 3.91 0.91 -0.30
Blake Hawksworth 40 4.69 2.03 3.83 2.66 -0.86
John Smoltz 38 2.98 4.26 2.75 -1.28 -0.23

A couple of quick thoughts –

  • John Smoltz is 43 years old. I get it. But he deserves a job, because he’s still really good at what he does. Discrimination against the elderly is an ugly thing, MLB general managers.
  • Our bullpen could really suck next year. Our best reliever is a LOOGY. Ryan Franklin, Kyle McClellan and Blake Hawksworth all had spiffy ERAs, but their SIERA indicates their skills are nigh replacement level. That doesn’t quite “feel” right, so take it for what it’s worth. I still get a sense of evil foreboding about our ‘pen for ’10.  Jason Motte on the other hand comes out looking like the Jason Motte we hyperventilated about not that long ago.
  • Revisiting the turd-storm that was the NL Cy Young this past season, Tim Lincecum’s SIERA was 2.73. Javier Vazquez was 2.87. Dan Haren’s was 3.37.  Just stirrin’ the pot.

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