Tuesday, September 25, 2012

Poster child for the problems with WAR

These are Adam Dunn's 2004-2010 seasons.  While I think that the 2004 season is his best and 2006 was his worst in this time period**, he was generally a model of consistency.  Unfortunately, while WAR and the human eye agree about his 2004 season, I can't wrap my head around the idea that 2009 was his worst NL season and 2010 was his third best.

GP AB H 2B 3B HR BB SO SB CS AVG OBP SLG OPS WAR
161 568 151 34 0 46 108 195 6 1 0.266 0.388 0.569 0.957 4.4
160 543 134 35 2 40 114 168 4 2 0.247 0.387 0.54 0.927 2.6
160 561 131 24 0 40 112 194 7 0 0.234 0.365 0.49 0.855 0.1
152 522 138 27 2 40 101 165 9 2 0.264 0.386 0.554 0.94 1.2
158 517 122 23 0 40 122 164 2 1 0.236 0.386 0.513 0.899 0.6
159 546 146 29 0 38 116 177 0 1 0.267 0.398 0.529 0.927 -0.6
158 558 145 36 2 38 77 199 0 1 0.26 0.356 0.536 0.892 2.2


Looking at Dunn's Player Value -- Batters table on baseball-reference.com, the problem is the vagaries of DWAR.  The OWAR rankings of his seasons fairly closely follow OPS (I'm assuming any slight differences are due to the fact that what constitutes a "good" OPS changed slightly from season to season), and thus the wild variation in DWAR, which is due more to the small-sample nature of defensive statistics than any actual change in performance, dominates the year-to-year differences in WAR.

OWAR DWAR
4.8 -1.2
4 -2.3
1.9 -2.4
3.7 -3.2
3 -3.2
3.7 -5.2
3.4 -2.1


While WAR isn't simply OWAR + DWAR, DWAR clearly plays an important role in devaluing WAR as an estimate of player worth in a given year, and I'd rather look at OWAR.  But if OWAR closely follows OPS over the course of a generation of players, then I'd rather simply look at OPS, which is more intuitive and immediately evident from the seasonal stats.

** I want to be absolutely, positively clear that we're talking about 2004-2010, and not looking at his 2011 season, which was arguably the worst all-time.

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