Thursday, July 24, 2014
Why WAR and not WAA?
There is a very strong appeal to WAA (wins above average). Average is so easy to calculate. So, why WAR and not WAA? Think about pitchers and nonpitchers. How much is an average pitcher worth and how much is an average nonpitcher worth?
First, what is an average pitcher, other than say he's a .500 pitcher?? We also need quantity. Not all .500 pitchers throw 180 innings. Some of them only throw 80 innings. Therefore, we need to merge quality and quantity to give us production. You can do this in two-steps, first compare both to average (i.e., .500), and then figure out the value of 180 innings and 80 innings. Let's say you come up with something that seems reasonable, then what?
The second thing you have to figure out is how to handle the .450 pitcher who throws 150 innings and the .500 pitcher who throws 80 innings. Should they be valued the same? Should the .450 pitcher produce more? Does the .500 pitcher produce more? And "production" is "contributions toward winning".
As you try to come up with various comparison points, you will eventually get to the point that no matter how many innings a pitcher throws, his production does not increase. That let's say you decide that a .400 pitcher who throws 8 innings, 80 innings, or 180 innings, it'll be irrelevant to a team's fortunes. His production, regardless of the number of innings, simply does not increase a team's fortunes. This is what we call the replacement-level player.
You establish the replacement-level baselines for all kinds of players and for all kinds of roles, be it starting pitcher, relief pitcher, PH, DH, C, SS, CF, 1B, etc.
And you also want to be careful that as a player moves from role to role that his production value doesn't change. It could change of course. Johan Santana switching from reliever to starter for example is the most prominent example, and points to the fact that he was either terribly miscast, or, it was part of the "process" (ala Earl Weaver's plan). But for established pitchers, we shouldn't expect their production level to change by switching between SP and RP. The idea is that a pitcher's talent level will dictate his role and his usage level and his leverage. Naturally, not everyone is optimized, so in some cases every year, pitchers are miscast.
Similarly with position players, as players are moved from SS to 2B or from CF to LF, their overall production level should remain fairly constant. In some cases it's not, as we're still identifying their optimal spot (say rookie Ryan Braun). But by and large, a player's production level won't depend on his position or role.
And that's what WAR gives you, that it establishes these various baselines so that you can in fact compare players across roles, and the confidence we have is that the "best player available for that role not in MLB" is worth the same regardless of role: nothing more than league-minimum.
WAR is the great equalizer. Is it perfect? What exactly is? But it's the best framework we've got, and rejecting it because it's not perfect still requires you to follow some model, however arbitrary, biased and capricious. And that model you will follow, even if it's just a jumble in your head, will be worse than WAR.
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