Stats Sunday – WAR

The following post appeared in 2012 as part of WGN’s Stats Sunday series. Thanks to Jonah Keri for this article.

The hot-button issue in baseball right now is the race for American League Most Valuable Player honors. Miguel Cabrera is threatening to win the first Triple Crown in 45 years. Yet despite his potentially historic season, Cabrera’s overall contributions actually fall short compared to those of Mike Trout. In fact, it’s not even close.

To understand how a player could contend for or even win the Triple Crown and not be MVP, we need to examine all the tangible qualities that go into making a great baseball player. One statistic that attempts to measure all those qualities is Wins Above Replacement, or WAR.

The premise of WAR is as follows: Start with the 25th man on a major league roster, or an effective Triple-A veteran. Acquiring such a player is something teams can do at little to no cost. Thus he’s what you would call a replacement-level player. By measuring other players’ contributions against that standard, we can better understand how well they performed in all facets of the game.

Let’s see Cabrera as an example. Leading the league (or even coming close) in batting average, home runs, and runs batter in is a tremendous feat. But it also paints an incomplete picture. How many singles, doubles, and triples has he hit on top of all those home runs? How many bases has he stolen, and how many times has he been thrown out? How often does he take an extra base when running the bases? What position does he play? Does he play that position well?

The three Triple Crown stats are silent on these and other factors that define a player’s performance. WAR, on the other hand, considers all of those factors, and more. And WAR favors Trout this season by a significant margin. Through Friday, Trout has delivered 9.7 Wins Above Replacement for the Angels, vs. 6.7 by Cabrera for the Tigers (using the <a href=”http://www.fangraphs.com/leaders.aspx?pos=all&stats=bat&lg=al&qual=y&type=8&season=2012&month=0&season1=2012&ind=0&team=0&rost=&age=&filter=&players=“>calculations provided by FanGraphs.com</a>). Extrapolating those numbers, if the Angels were, say, an 80-win team with a scrub playing instead of Trout, they’d be roughly a 90-win team with Trout. Run the same math for Cabrera and the Tigers go from being an 80-win team to roughly an 87-win team. (The gap is even wider is we use <a href=”http://www.baseball-reference.com/leaders/WAR_top_ten.shtml“>Baseball-Reference.com‘s</a> calculation for WAR; Trout comes in at 10.5 WAR through Friday, Cabrera 6.6.)

So what constitutes a good WAR score, vs. a bad one? Roughly speaking, a player who accrues zero to 1 Win Above Replacement in a season is either a lousy everyday player, or a bench jockey. A 2-WAR player is a league-average starter. Rack up 3 to 4 WAR in a season and you’re a good to very good regular. A 5-6 WAR player is a star. Anything above 6 Wins Above Replacement and you’ve got a player who should make it onto MVP ballots.

Like any other stat, WAR isn’t perfect. We’ve noted that different sites use different measures to calculate it, for one thing. Also, WAR uses a defensive stat called Ultimate Zone Rating to measure a player’s defense. UZR’s a major upgrade over, say, fielding percentage, in that it seeks to pinpoint actual runs saved by fielders rather than merely assigning them an error or non-error based on the discretion of the official scorer. But UZR is still an estimator, one that gains more reliability the larger the sample size in question is. To gain a better measure of a player’s defensive value, looking at three years of UZR data is more instructive than a single season.

Still, the idea of considering a player’s full breadth of skills rather than simply evaluating an individual stat or three has merit. It can help teams better understand what they’re buying when they trade for a player or spend big bucks on the free-agent market. And when it comes to sizing up two of the best players in baseball for postseason hardware, it can tell us a lot.

Jonah Keri (@jonahkeri) is a staff writer for Grantland. His book, The Extra 2%: How Wall Street Strategies Took a Major League Baseball Team from Worst to First, is a national bestseller. His book on the definitive history of the Montreal Expos comes out in 2014.

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