Stats and Musings: Possession, though not everything, indicates MLS styles

Let's first run through a few things we know about possession statistics before we wonder how they relate generally and how they relate across the league. First, it's generally not literal possession. Simply, the possession stat, as displayed by Opta, is a rather simple measure of total passes attempted by a team. They have conducted studies (apparently) indicating that this is in all but rare circumstances, a figure which is nearly identical to a literal possession figure. I have no problem with this. Second, we know that possession is far from everything. I'd like to see how much it means across the league, though, and what it means for different teams.

Let me also temper things a bit by acknowledging that there will be some rounding errors involved, so stats will not quite reach 100 percent. That is what it is, and the less than one percent involved is basically inconsequential.

Winning Possession: The margin between the winning team's possession — or passing ratio, if you are striving for accuracy, though I will use the term possession for ease of use — and the losing team's possession is really quite small. The winning team — and this surprised me a bit — is at 48.56 percent possession on average so far this season, while the losing team is just a hair over 50, at 50.6 percent. (Rounding errors, remember.) At the very least, this indicates that possession generally is not a good indicator of who wins a match, at least when considered on a league-wide basis.

Home and Away: When the home team wins a match, though, possession is at 50.27 percent, and when the away team wins, possession is at 45.13 percent. What exactly does this mean? It's hard to really say on a league-wide basis, but it's a bit fascinating, isn't it? It's below even the general away possession percentage, 47.6 percent. However, it's well within one standard deviation of the average away possession, which may temper things a bit. Possession during draws by away teams is also right there with the away stat generally, sitting at 47.47 percent.
On from the general things, though, which really don't tell us

Looking at team-specific stats is more elucidating. Some teams are clearly more oriented toward playing without the ball, and whether this means they make more their time with it or they make more of an effort to retain a solid defensive shape and are more content to boot it away, it's hard to say. But here it is.

When-Winning Possession: The teams at the top of the when-winning percentage — those above 50 percent — are not entirely surprising. Sporting KC sits at 51.33 percent, while Colorado Rapids, who have been good with the ball this season, especially with the solid performances of Jeff Lawrentowic, sit at 51.63 percent, placing them third in the league. Second in the league sits Real Salt Lake, with 53 percent possession during wins. At the top of the league sits Houston Dynamo at 57.45 percent, which comes as a slight surprise to me, but they're a side that, when they've done well with the ball, generally capitalize on it.

The teams at the bottom — and keep in mind, this isn't meant as a pejorative claim — are Toronto FC, with 40.6 percent possession during their five wins. Next up, Real Salt Lake's next opponents, Vancouver Whitecaps — a side very efficient without the ball — at 43 percent. New England Revolution are at third, with 43.67 percent. LA Galaxy aren't far behind in fourth, with 44.5 percent possession when winning. These sorts of teams, when they win, tend to make the most of their time on the ball, whether that comes through set pieces, through counterattacking play, or through a general sort of defensive mindset. Indeed, it's interesting to note that only four  teams — the four mentioned above — hold more than about 50 percent possession during their wins. Don't color me surprised, but I'd reckon this speaks more to the league style than the general averages detailed above.

When-Losing Possession: If the when-winning possession tells us the general style teams employ when they're at or near their best — or at least better than the opposition — than the when-losing possession percentages should give us an idea as to the factors. Not many clues, mind, but perhaps a few. The order shuffles around somewhat, so let's have at it.

The team that possess the ball the most when losing? New York Red Bulls at a shocking 55.71 percent — ahead of their 52.04 percent possession average this season. Though their fortunes have been somewhat brighter this season than last, their inability to find a result when they control the ball has plagued them somewhat. It is perhaps for this reason that they've sought to bring in another striker in Tim Cahill, such is their lack of chance-creation and chance-finishing.

Up there with New York are Sporting KC (54.43 percent, to 52.35 percent overall), Colorado Rapids (54.07 percent, to 53.2 percent overall), and Chivas USA (54 percent to 49.95 percent overall). While Sporting KC and Colorado seem to maintain the same sort of play, the disparity shown by New York and Chivas USA indicate a misuse of possession during losses. Whether this indicates something broader about the teams they play, or if it speaks more to their abilities, it's clear these teams have run into some distinct problems.

So while these possession numbers might mean something different than what might be intuitively considered, they clearly speak to something, particularly when taken in relation to wins and losses. Now, it doesn't mean that allowing a team the ball might lead to their losing — that's a dangerous road to go down — but they do allow some introspection that might be otherwise missed.