Library Update: wOBA and wRC+

A couple of weeks ago, we announced a renewed commitment to the FanGraphs Library and promised regular updates to glossary entries and blog posts. You’ve probably noticed our weekly FanGraphs Q&A chats at 3 p.m. EST on Wednesdays, but the other changes to the library aren’t necessarily obvious on the site’s main page.

If you haven’t had a chance to check out the changes to the library, the entries on Weighted On-Base Average (wOBA) and Weighted Runs Created Plus (wRC+) have been updated and include more current information, a more thorough explanation of how and why you should know and use these stats, and for the first time at FanGraphs, information on how to actually calculate wRC+.

Additionally, you’ll find the library’s blog populated with a couple of posts discussing the importance of learning wOBA and wRC+.

If you’re looking for information on other statistics we offer, on how to make use of various FanGraphs features, or if you have related questions, check out the weekly chat, comment on this post or posts in the library blog or contact me on Twitter @NeilWeinberg44. We’ll roll out more educational posts and glossary updates each week, so be sure to check often.




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Neil Weinberg is the Site Educator at FanGraphs. He is also the Managing Editor at Beyond The Box Score and can be found writing enthusiastically about the Detroit Tigers at New English D. Follow and interact with him on Twitter @NeilWeinberg44.


24 Responses to “Library Update: wOBA and wRC+”

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  1. #KeepNotGraphs says:

    #KeepNotGraphs

    +15 Vote -1 Vote +1

  2. AC_Butcha_AC says:

    Hey Neil,
    I think I found a minor mistake in your wRC+ library entry.

    You said:

    “Next we have league average runs per plate appearance which is available on the Guts! page, just like all of the other constants. This is simply the MLB wRC divided by the total number of plate appearances across the game during that season. We round this off at three digits in the table, so if your calculation is ever off by a small margin, this is likely why.”

    Actually, R/PA in the Guts! page is league wide runs scored, pitcher hitting included per PA. In 2012 (the year of your exemplaric Trout season) you couldn’t tell the difference, because of rounding so both calculations came out to .114. But take 2013 as an example: lgR=20255. lgwRC=20189. lgPA=184873. lgwRC/lgPA=.1092. lgR/lgPA=.1096. With rounding you get .109 for the wRC calculation and .110 for the actual runs scored calculations – the same number as on the Guts! page.
    Nevertheless, I love your effort and please keep up all the good work :)

    Vote -1 Vote +1

  3. Russ Adams says:

    Why are intentional walks excluded from wOBA? They are still valuable, the batter is not making an out and is still creating offence.

    Also is it an intentional walk when the batter lays off 3 really close pitches and the third one is intentionally thrown as a ball? Even though the pitcher initially was trying to retire the batter.

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  4. Brian says:

    I vote for one more category below awful.

    <40 Dan Ugglesque

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  5. BrickSkuad says:

    Hi Neil,

    So if wOBA and wRC+ are context neutral, is there an existing metric that tries to quantify a players contribution in specific instances of a game? If so what would this be called? (apologies if the answer is in the library index already)

    Thanks!

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    • joser says:

      One attempt is clutch.

      Vote -1 Vote +1

    • RE24 and WPA both do that in different ways. RE24 focuses only on the base-out context (i.e. man on first, one out) while WPA includes that and the score/inning of the game. Our sections explaining those in detail are a bit thin, but they will be updated soon and you should be able to find a good amount of info online or by asking!

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  6. Phillies113 says:

    If wRC and wRC+ are calculated using league wOBA, than how is league wRC calculated? Wouldn’t league wOBA cancel itself out, leaving simply unadjusted runs per plate appearance?

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    • I’m not entirely sure what you mean. The full equation is here: http://www.fangraphs.com/library/offense/wrc/

      Can you clarify your question?

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      • Phillies113 says:

        wRC = (((wOBA-League wOBA)/wOBA Scale)+(League R/PA))*PA

        Per this equation, if I’m trying to find the league’s wRC, wouldn’t “wOBA” and “League wOBA”, as defined above, be the same? In that case, they would cancel out to zero, since you’re subtracting a number from itself, leaving the left side of the equation equaling zero.

        I’ll admit that I’m very new to all this, and I leave it wide open that I’m missing something crucial (which I undoubtedly am).

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        • MathCounts Coach says:

          League wRC = (((League wOBA-League wOBA)/wOBA Scale)+(League R/PA))*PA
          = ((0/wOBA Scale)+(League R/PA))*PA
          = (0+(League R/PA))*PA
          = (League R/PA)*PA
          = League R

          The “better/worse than average” term goes to 0, and you’re just left with the league runs total. Which is to say, League wRC is not a meaningful stat.

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        • You’re right on the raw equation side of things.

          wRC is always lower than runs scored for the entire league, by about 60-80 per season, or a tiny tiny fraction per PA.

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        • Phillies113 says:

          (I’m replying to MathCounts Coach below. Hopefully this comment winds up in the right place; I didn’t see a reply button for him/her specifically)

          I understood the math involved. I was just wondering if there was a material difference between League R and wRC; as of now, the former reads 12,562 while the latter is 12,514. It’s a slight difference, so I wasn’t sure if there was significant difference between the two or not. Thanks to you, I now know there’s not.

          Thanks for the help!

          Vote -1 Vote +1

  7. HawaiiFO says:

    BsR is not a component of wRC+. (The SB/CS part used to be at one time but not extra bases advanced)
    So if you want one number on a players “total runs created”; as opposed to “total runs created with just the bat”, there is OFF.

    Quickly without looking, what’s a good OFF number right now in baseball at this time of the year?
    OFF is not splitable or set to 100 like wRC+ so it isn’t easy to use, and it isn’t easy to use when comparing a platoon situation among other things.

    #1 why take out BsR? looking at two runs created numbers separately is complicated.
    #2 why not also have a splitable, set to 100 stat like (wRC+BsR) or (OFF+) to easily compare “Total runs created” with just one stat?

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    • We made the determination that wOBA and wRC+ were best as measures of hitting performance. That’s how it was originally intended and it made more sense to present it that way.

      If you’re looking for something like OFF+, you can compare each player’s OFF/PA, that will provide you reasonably similar information.

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  8. Jordan says:

    Keep up the good work Neil! I’ve really appreciated your contributions to the site.

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  9. A different Mike says:

    Any chance wRC+ for the minors gets developed to the same level of the majors – making it both league and park adjusted?

    Vote -1 Vote +1

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