Cameron: Putting WAR in context: a response to Bill James

From Dave Cameron at FanGraphs on November 20, 2017, with mention of SABR member Bill James:

Nine years ago next month, we introduced a new stat to the pages of FanGraphs. We called it Win Values, and on the player pages and leaderboards, it went by the acronym WAR. We wouldn’t actually start calling it that, or use the words for which the acronym stood (Wins Above Replacement) for a little while, since we thought Win Values sounded cooler. And as the people who bring you WPA/LI and RE24, we’re clearly the experts on statistical naming coolness.

Over the last nine years, WAR has become something of a flagship metric, not just for us, but for the analytical community at large. Baseball-Reference introduced their own version, while Baseball Prospectus modernized their version of WARP — their version adds the word player to the name, thus the P — to provide something that scaled a bit more like what was presented here and at B-R. Because WAR is a framework for combining a number of different metrics into a single-value stat, there are also quite a few other versions of WAR out there, each with their own calculations.

But while everyone uses different inputs — and therefore arrives at slightly different results — almost all of the regularly updated WAR metrics are built on some version of linear weights, which assigns an average run value to each event in which a player is involved, regardless of what actually happened on the play. If you hit a single, you get credit for hitting a single. It’s worth some fraction of a run, regardless of whether you hit it with two outs and the bases empty in a the first inning of an eventual blowout, or whether it was a walk-off two-run single to give your team the lead. In most versions of WAR, the value of a player’s contribution is calculated independent of the situation in which it occurred.

Bill James is not a fan of that decision.

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Originally published: November 20, 2017. Last Updated: November 20, 2017.