Baseball for the Thinking Fan

Login | Register | Feedback

btf_logo
You are here > Home > Baseball Newsstand > Baseball Primer Newsblog > Discussion
Baseball Primer Newsblog
— The Best News Links from the Baseball Newsstand

Sunday, April 20, 2014

Studeman: Why wOBA Works

Why wOBA Works

Let’s say you have a player, let’s call him Al Trout, who has hit six singles in 10 plate appearances (making an out every other time) and the league, on average, hits three singles every 10 plate appearances (again, making an out every other time). To use linear weights to figure out how many more runs Al contributed above the league average, you’d…

  Calculate the extra runs Al contributed by hitting more singles, which equals the difference in singles times the run value of a single, or (6-3) times 0.48, or 1.44.  Then you’d…
  Calculate the extra runs that Al contributed by making fewer outs, which equals the difference in outs made times the run value of an out, or (4-7) times -0.30 (that’s a negative 0.30), or 0.9. Then you’d…
  Add the two together. 1.44 plus 0.9 equals 2.34. In his 10 plate appearances, Al contributed 2.34 runs more than the average player.

Okay, I have to add a technical footnote here. I have shown you this way of calculating linear weights because it will make it easier to understand the wOBA formula But, in reality, you only have to multiply Al’s singles and outs by the appropriate linear weights of that league and year to calculate the number of runs he contributed above average.

Anyway, that’s the hard linear weights way to calculate the difference.  Here’s the wOBA way:

  Multiply the difference in singles times the wOBA multiplier, or (6-3) times 0.78, or 2.34.

That’s it; one simple step. wOBA shows that Al contributed 2.34 runs more than the average player, the same outcome as the linear weights.

Why does this happen? Because wOBA weights include the impact of the hit AND the impact of turning an out into a hit. When you keep the number of plate appearances even, you’re not just adding a hit to the hit total.  You’re also reducing an out from the out total. wOBA captures the impact of both event changes.

wOBA fundamentally works because it is a rate stat.  Its divisor is plate appearances. When you compare two players’ wOBA you have equalized their total plate appearances.

Thanks to Los.

Repoz Posted: April 20, 2014 at 05:27 AM | 1 comment(s) Login to Bookmark
  Tags: sabermetrics

Reader Comments and Retorts

Go to end of page

Statements posted here are those of our readers and do not represent the BaseballThinkFactory. Names are provided by the poster and are not verified. We ask that posters follow our submission policy. Please report any inappropriate comments.

   1. Walt Davis Posted: April 21, 2014 at 06:09 PM (#4690582)
wOBA is just oRAR/PA, pointlessly (and incorrectly) re-scaled to an OBP-like measure. (or the hitting-only component of oRAR if you don't want to include baserunning) That's it, nothing special.

You must be Registered and Logged In to post comments.

 

 

<< Back to main

BBTF Partner

Support BBTF

donate

Thanks to
Mike Emeigh
for his generous support.

Bookmarks

You must be logged in to view your Bookmarks.

Hot Topics

NewsblogOT: Monthly NBA Thread - May 2015
(2873 - 12:41am, May 30)
Last: Win Big Stein's Money

NewsblogAn advance scout's theory on why A-Rod is so good this year - NY Daily News
(59 - 12:25am, May 30)
Last: Cloude Atlas (Voxter)

NewsblogOT: Soccer March 2015
(1281 - 12:21am, May 30)
Last: Jose Is The Most Absurd Thing on the Site

NewsblogThe Astros Are Making A Historic Turnaround
(1 - 12:16am, May 30)
Last: Baldrick

NewsblogDan Uggla is a good hugger, Washington Nationals say
(12 - 12:16am, May 30)
Last: Cloude Atlas (Voxter)

NewsblogOMNICHATTER 5-29-15
(93 - 12:05am, May 30)
Last: Pirate Joe

NewsblogOTP - May 2015: Jeb Bush would like to watch baseball with Teddy Roosevelt and Pitbull
(4674 - 11:59pm, May 29)
Last: Howie Menckel

NewsblogOT: 2015 NHL Playoff thread
(585 - 11:33pm, May 29)
Last: Howie Menckel

NewsblogPrince Fielder’s Foul Ball Lands In Woman’s Nachos; Cheese Goes Everywhere [VIDEO] « CBS Detroit
(14 - 10:47pm, May 29)
Last: Srul Itza

NewsblogLet's play two: Baseball would be better with a split season | FOX Sports
(33 - 9:02pm, May 29)
Last: cardsfanboy

NewsblogFire Ben Cherington and John Farrell? That’s not going to happen - Sports - The Boston Globe
(86 - 8:04pm, May 29)
Last: Squash

NewsblogFor de Blasio, a Red Sox Fan, the Simple Pleasure of Baseball Gets Complicated
(13 - 6:37pm, May 29)
Last: Dog on the sidewalk

Newsblog5-28-2015 OMNICHATTER
(63 - 4:27pm, May 29)
Last: boteman asks Where's My Ring?

NewsblogIn Which Derek Norris is Blamed for Home Run Problems, Plight of Humankind | Padres Public
(15 - 4:12pm, May 29)
Last: Al Kaline Trio

NewsblogOT: NBC.news: Valve isn’t making one gaming console, but multiple ‘Steam machines’
(1682 - 3:39pm, May 29)
Last: DJS From Suplex City!

Page rendered in 0.1720 seconds
48 querie(s) executed