WAR Diagram: Position Players
Wins Above replacement (WAR) is probably the best known composite statistic that attempts to estimates the entire value of a player to a team in a context-neutral and park-adjusted environment. It is also an incomplete model, and while we’re always trying to make it as comprehensive as possible, that does require updating the formula from time to time; just this past March we added a few more things to try and make it even better.
In an effort to increase understanding of the all the factors that go into calculating WAR, I have created the following diagram to the various player statistics and league average values which have gone into the calculation. Our goal is to always make the process as transparent as possible, and hopefully this infographic can help on that path.
DISCLAIMER: This diagram is meant to summarize the process of calculating WAR, it does NOT contain every detail necessary to accurately perform that calculation. For a full description of the formulas and equations please see the library page, which more fully explains the process.
The very left of the diagram contains the stats which are the basic building blocks of WAR. These include the familiar walks, singles, doubles, triples, and home runs along with the alphabet soup metrics: UBR, wGDP, UZR, and RPP. Most of the latter stats are built on proprietary data, so you won’t be able to calculate our version of WAR from scratch yourself, though you could substitute your own fielding and baserunning metrics.
The right side contains the finished product, a player’s WAR components. The oval shapes represent inputs, while the rectangle shapes represent calculated components which are steps along the way to get WAR.
The WAR diagram is divided into six component areas: Batting, Base Running, Replacement, League, Positional, and Fielding. Four of those six areas also fall under either the Offensive or Defensive region, which are the greatest differentiators of talent. These areas represent different WAR component stats we host on FanGraphs in our Value section on our leaderboards.
The runs from the six areas are aggregated to yield runs above replacement (RAR), which is then converted into wins using each year’s specific R/Win ratio, and that resulting value is WAR.
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What’s really cool is that you can see the “framework” of WAR, as Tom Tango calls it, at the highest level of the diagram.
For example, if you wanted to scrap the whole “Batting” box with any formula for runs above average (even using, say RBI), you’d still technically be using the WAR framework, just measuring it differently than most folks would. The key steps in the WAR framework will always be (1) estimate how many runs a player has contributed above or below average, in all facets of the game, (2) compare that to the performance level of a marginal MLB player, taking into account positional scarcity, and (3) convert from runs to wins.