Stats: An Ode to Variance

If you read the starts articles I scrawl out on here occasionally, or any of the related content we link to, you'll note that I mention fairly often that soccer is a sport in which short term results — compared to other sports — are highly dependent on luck. I don't want to belabor the point, but for this one post I'll belabor it like a rented mule.

I wrote a series on parity in MLS compared to other leagues and sports a few years ago. Here's the entry on Game Parity which is related to the likelihood that the better team will win a single game. Soccer and baseball stand out as games in which the better team still loses a lot of games. Both are relatively low scoring and it's common enough for a 'worse' team to bang out a couple of runs or goals and steal a win. Even the completely horrible Mariners teams of recent seasons still win a third or so of their games. But baseball has a 162 game season to sort out the teams. MLS has just over thirty. In MLB, a ten game winless streak can just be a bad run. In MLS that's a third of your season and suddenly you're unlikely to make the playoffs.

The hoary saying among coaches and fans is 'goals change games', which is painfully close to tautological since goals are literally how games are decided according to the rules. The more interesting fact is that when you go back a step, tiny bits of unpredictable variance decide goals, and therefore decide games. Coaches tend to talk in terms of 'chances'. Teams create chances with training and talent and good play, but then you're basically just hoping for a chance to turn into a goal. If your chances don't turn into goals your results suffer. If they do, suddenly you're on a points streak. You need look no further than Seattle's last two results to see that.

If not for Aurelien Collin completely missing a clearance in injury time on Wednesday and Zac MacMath inexplicably standing behind his line on a corner on Saturday, Seattle would be looking at a loss and a draw and 1 point in its last two matches instead of a win and a draw and an impressive 4 points in a tough road trip.

Usually when we say something like "If not for X, the result would have been Y" there's a lot of sleight-of-hand going on. Changing a single event would have a rippling effect and change the rest of the game completely, like a butterfly flapping its wings in China eventually creating a breeze that tousles Martin Rennie's perfect coif on the other side of the world.

But when Djimi Traore scored his second most memorable Sounders goal on Wednesday, it was one of those rare instances when we can be pretty confident that the result would have changed. The goal came, like most of our goals against Kansas City, deep in injury time. And if Collin hadn't missed on his attempt to clear the ball, if he'd actually made contact and booted that ball out of the area like he would in 49 attempts out of 50, there's about a 99% chance that the game would have ended in a tie. There just wasn't time for much of anything else to happen. So we can say the inch or two that kept him from getting to that ball — the microsecond difference in eye-hand coordination or the tiny bit of looseness in the pitch that adjusted the trajectory of his foot, meant the two-point difference between a Seattle win and a draw.

A similar play happened the previous match against Philadelphia, though that was much earlier in the game so you'll have to indulge me in assuming for the sake of argument that the the butterfly wouldn't have flapped and the rest of the game would have played out the same. When Eddie Johnson knocked in his header to open the scoring in that game, Union keeper MacMath was standing behind his line. Which is why, even though the ball went straight into his chest, the result was a goal. Because for some reason his chest was inside the goalmouth. Ninety nine times out of a hundred, a keeper is in front of his line there — even a keeper as inexperienced as MacMath — and that ball drops down for an easy pickup. And if all else stays the same, Seattle loses 1-2.

The reason I think it's important to re-iterate this stuff is that it's a massive factor that's completely and intentionally ignored in most analysis. Sports coverage — and really any ongoing news story — is at core written as a narrative. We call them 'stories' for a reason. The human mind likes stories, with familiar themes like hubris and redemption and life journeys and so on, and we pound the raw material of facts into those stories like a blacksmith sweating at an anvil. And that's fine and satisfying and enhances our experience of the game, but it's not hard analysis. And it's important to remember how tenuous the foundations of those stories are.

After the closed-door meeting after the fiasco against Real Salt Lake, Seattle has gone an undefeated 2-0-2. That's a nice story. But Collin didn't whiff on his clearance because Sigi chewed the team out over a month ago. MacMath didn't stand two feet further back because of whatever was said in that meeting. But because they did we're going to build that narrative. That's not to say that that meeting didn't matter. None of this is to say that motivation and nutrition and training and talent are all meaningless and we're just rolling dice out there on the field. It's to say that in the short term two pro teams are close enough in motivation, nutrition, training, and talent and the inches that lead to goals are so important that weird factors dominate games. And short term game results dominate narrative. So now we're talking about a team ascending back to its familiar place as a contender even against the toughest competition instead of a team still mired in one of its worst runs in its MLS history, because of two inches in Kansas City and two feet in Philadelphia. In next week's power rankings Seattle will be somewhere in the middle. If two inches here and two feet there had changed, they'd be near the bottom.

I don't want to ruin the party after last night's win, because this team is legitimately good and deserving of more results than it's gotten. But I think it's always important to keep in mind how small and fragile are the foundations of these narratives, and ultimately the jobs of the players and coaches and the fortunes of the franchises that depend on those narratives.

There's an alternate world not far away where we didn't get those points, and we're seriously talking about Sigi's job. We're talking about making dramatic moves in the summer window so soon after making dramatic moves to start the season. That's the knife edge that MLS teams live on.