WAR and the 2009 Mariners
A few facts you’ve probably heard tossed around the last few days:
1. The Mariners won 85 games
2. The M’s were outscored by 52 runs
3. Their pythag record, based on the above run differential, was just 76-86.
People have extrapolated all kinds of things from those facts. One of the more popular explanations for those three facts is that the team isn’t as good as their final record indicates, and that the extra wins are either due to unrepeatable good luck or the bountiful harvest of unquantifiable team chemistry. I’m here to say that both of those explanations are bunk.
Run differential is a decent tool when its used correctly and its limitations are understood. Good teams have large positive run differentials, bad teams have large negative run differentials, and teams in the middle are generally mediocre. It’s pretty hard to succeed without regularly outscoring your opponents, as should be pretty obvious, and no team is good enough to consistently win enough one or two run games to overcome a lack of talent. So, you can generally do a pretty decent job of projecting a team’s Win-Loss record based on RS-RA. No team was more than +/- 9 wins away from their pythag record this year, for instance.
That said, run differential is certainly not a perfect estimator of a team’s real abilities. Run totals can be skewed heavily by performance with men on base, either by hitters coming through in the clutch or pitchers stranding runners. In general, teams do not have a real ability to be significantly better or worse than you would expect in these situations based on their overall production, but over the sample of one season, teams performance can vary enough to affect their run totals. And that affects their pythag record, even though it’s not a real indicator of talent.
This can have a real impact on how people see a team overall. Not surprisingly to anyone who watched regularly, the Mariners were the worst hitting team in baseball with runners on base this year, hitting .254/.317/.396 with a man on. They were also worst in baseball at hitting with runners in scoring position, coming in at just .234/.312/.358. As a team, the M’s hit better with the bases empty than in pretty much any scenario where they had a chance to drive in a run (which is not normal, if you’re wondering), and while that’s frustrating to watch, it’s not an indicator that the M’s were really the worst offense in baseball – they were just a bad offense that failed in the clutch more often than they should have. And that skews their runs scored total down, which pushes their pythag record down, and, well, you get the idea.
Anyway, that’s a lot of words used to say that pythag is not luck independent, and shouldn’t be used as the be-all, end-all determinant of how “good” a team really was. In fact, we have a better way of measuring team talent level, and it’s one you should probably be familiar with by now – Wins Above Replacement.
You’ve seen us talk about WAR a lot. It’s the best measure of player value that we have, and while it’s not perfect, it’s pretty darn good. It sums up a player’s offensive and defensive value, as well as accounting for time on the field, and puts it on a scale over the production that could be expected from a pretty good Triple-A player would offer for the league minimum. At the team level, it’s the total of all the wins added by players on the roster throughout the year. And, because all of the inputs used in the formula are context free, it doesn’t know anything about the timing of specific events and isn’t affected by “clutch” performances in the way that run totals are.
WAR is a better indicator of talent level than pythag. And you know what WAR thought the M’s record “should be” this year? 83-79. The M’s got 21 wins from their position players (mostly thanks to their league best defense) and 16 wins from their pitching staff. Based on the calculations from FanGraphs, a replacement level team this year would have won ~46 games, so add those 46 wins to the 37 extra that the M’s got, and you have 83 expected wins.
In other words, the M’s weren’t a 76 win team that got really lucky or willed themselves to 10 extra wins through their harmony and hugging. They were a team that played well enough to finish two games over .500 and actually finished four games over .500. There’s nothing to explain. The M’s finished right about where we’d have expected them to, given how well they hit, caught, and pitched.
Don’t let the Pythag Police try to convince you that there’s an inevitable massive regression coming because the M’s outperformed their pythag. Their pythag underperformed their actual offensive level, and once you adjust for all of the facts that could be considered “luck” (not just some of them, as pythag does), you have to conclude that the M’s were basically the team that their final record indicates. There is certainly still a lot of work to do to get this team to be a playoff contender, but in order to know how much work needs to be done, you have to start from the right foundation. And that foundation is not pythag record.