Explaining Terms is a many part series in which I explain certain Sabermetric terms in order to make them more accessible.
WAR, or Wins Above Replacement, is a statistic which is intended to give a reader a holistic view of a player’s performance.
- WAR is a cumulative counting stat, so higher is better, but be wary of high WAR totals in a large number of PAs.
- The average WAR per 600 plate appearances is 2.0.
- WAR is measured in wins, which are meant to be directly applicable to team wins and losses.
- 1000 WAR is handed out every year by Baseball Reference and Fangraphs, each. Both websites have proprietary techniques to calculate WAR; to differentiate, Baseball Reference WAR is called rWAR and Fangraphs WAR is called fWAR.
- WAR is league adjusted, context neutral, and park adjusted.
- For pitchers, fWAR is intended to be fielding independent, while rWAR is intended to be fielding dependent. Both have their detractors, but both are incredibly useful.
WAR is a combination of every commonly quantifiable aspect of a baseball player’s game. WAR for position players combines hitting, fielding, baserunning, a positional adjustment, and the nebulous value over replacement level. For pitchers, WAR is calculated by ascertaining runs saved relative to replacement level.
But what is replacement level? That’s the theoretical point of talent at which players are ubiquitously available at the league minimum of approximately $500,000. In other words, replacement level players can theoretically be attained at any time, so any player worth playing has to be more valuable than that. A team full of replacement level players is assumed to attain a .294 winning percentage, or 47.7 wins in a 162 game season.
Calculating WAR for hitters is rather easy once you have the components. Finding the components might be tricky, but I will explain those in another post.
Batting WAR = (Batting Runs + Fielding Runs + Positional Runs + Baserunning Runs + Replacement Runs) / lgRuns Per Win
lgRuns Per Win is the league average rate of runs that each win above replacement is worth, and it varies slightly from year to year; however it does vary nontrivially over long periods of time. Here is a table with the values. Replacement Runs is assumed to be 20.
WAR for pitchers is substantially more difficult. I may make a post about it in the future, but it is quite a bit of pain for an unsubstantial gain to explain, and my patience with it wanes. I hope you don’t find my rhymes lame.
As always, feel free to ask questions in the comments.