Sports Reference Blog

Everything You Wanted to Know About Wins Above Replacement (WAR)

Posted by Neil on June 5, 2013

With Wins Above Replacement (WAR) gaining more prominence since last season, it's a good time to remind everyone about our WAR 2.2 guide:

  • WAR Explained - This explains the basics of WAR, the philosophy behind the stat, and some of the changes we made to the formula the past few years.
  • Weighted Runs Above Average (wRAA) Explained - This describes how wRAA, the core hitting stat of WAR, is computed.
  • Position Player WAR Calculations and Details - This explains how we turn wRAA, Baserunning & Double-Play Runs, Fielding Runs, Positional Adjustment Runs, and Replacement level Runs into WAR for position-players.
  • Pitcher WAR Calculations and Details - This explains how we take a pitcher's runs allowed & innings pitched, and turn it into WAR.
  • Converting Runs to Wins - This further describes the process by which Runs Above Replacement (for both pitchers and position players) are converted into Wins Above Replacement.
  • WAR Comparison Chart - This chart shows the differences between the WAR found here at Baseball-Reference and those from a variety of other sources, including FanGraphs & Baseball Prospectus.
  • WAR Data Downloads - If you want to download the raw WAR data yourself and play around with it, you can also get the Batting and Pitching data from our site.

Many of the questions we typically get about WAR can be answered by reading the guide linked above.

8 Responses to “Everything You Wanted to Know About Wins Above Replacement (WAR)”

  1. All there is to know about WAR Says:

    [...] [...]

  2. Ty Says:

    How do you calculate offensive win%? I know that it means if there was a line-up of the same player, but what is the formula that is used to get offensive win%? I assume it is related with oWAR?

    I have another question, how many runs would a replacement level line-up score in a typical league year (say, 2012, AL and NL), and how many runs would a replacement level pitching staff give up in a given league year (2012, AL and NL)?

  3. Neil Says:

    The OWn% you see under "Advanced Batting" isn't based on WAR, it just uses the old Bill James formula using the pythagorean theorem and runs created/27 outs to what a team of 9 clones of the guy would win with avg run-prevention.

  4. Neil Says:

    We set the replacement level to a .294 team in March. The avg 2012 team scored and allowed 701 runs. Using pythagorean wpct and assuming this replacement team was equally worse than the MLB average on both offense and defense, to get a .294 wpct you'd need a team that scored 151 fewer runs than average and allowed 151 more runs than average -- in other words, a team with 550 RS and 852 RA. That team would go (550^2)/(550^2+852^2)=0.294.

  5. Ty Says:

    Thanks, Neil. I would assume RA and RS would be a litter higher in the AL, and a little lower in the NL. The 852 RA seems a bit low to me, but I looked at the worst run prevention teams last year and Colorado came up last at 5.5; they played in Coors Field, with, for the most part a 4-man rotation, which would clearly increase the RA values.

  6. neal Says:

    Hello, I'm looking up splits, both batting and pitching. you have war for total pitch. but if a person goes to relief pitch, you don't have the war. is same thing. In batting if I go to position batt. like 1st base you don't have it for that. So I
    was just wondering why you especially relief pitch. A person can go to relief pitch on PI and have war but they have a few games as starter in it. thank you.

  7. tomfromnorton Says:

    The defensive value of the overall WAR statistic is my pet peeve. I think it's way overvalued in the overall WAR calculation and now I a new complaint. How in heck? does Roberto Clemente have a dWAR of -0.6 in 1961!!! This is the year he had his all time high of 26 outfield assists. He is the career leader in the modern error of baseball in career assists and I think for the most part no one would argue he had the greatest outfield arm in the last 60+ years. But guess what, he had a negative overall defensive value in 1961!!! Really??? His other defensive stats don't seem horrible to me so could someone??? anyone??? please explain to me how the great Roberto could be valued less than a REPLACEMENT player.

  8. Neil Says:

    #6 - We don't split out WAR by relievers vs starters. You just get WAR.

    #7 - "Defensive WAR" is not measuring vs a defensive replacement level -- it's actually just wins above average, basically, adjusted for position. Clemente was 0.5 runs above average defensively (+6 for his OF arm, but -5.5 for his zone rating) at a position (RF) with a -6 positional adjustment, so his defense was -0.6 wins above average in 1961.

    In this sense, the term "Defensive WAR" is somewhat misleading, because it's measuring vs. average, not a replacement level on defense. Then again, research has found that the typical replacement-level player is a horrible hitter but actually a league-average defensive player. This suggests that, on the waiver wire, it's not hard to find a guy who is an average fielder but can't hit, which intuitively makes sense even from a non-stats perspective.