USA TODAY Sports
Tempo Free Soccer publishes a league table with expected goals and expected points per match. What can we learn from the data they're producing.
I got turned on to Tempo-Free Soccer yesterday, and while I'm not great at generating data I love digging into and trying to understand someone else's. They've got up the first Tempo Free Table of the year, and I thought I'd take a whack at trying to explain what all those numbers mean.
What TFS tries to demonstrate is soccer efficiency; what are teams doing with possessions when they have them. As possession alternates, each team should finish a match with the same amount of possessions, and over the course of a season you get a sense of what sort of style different teams have.
For example, last year San Jose was criticized for not valuing possession enough and playing a very high tempo style, but they weren't the leaders in possessions per match (link). That honor belonged to the Seattle Sounders, with the Galaxy coming in 6th behind the 5th place Earthquakes. The bottom of the possessions per match pile is defensively praised Real Salt Lake, and Chivas USA was dead last.
The biggest component in calculating possessions, according to Tempo-Free soccer, is Opta's tackled and possession lost (link). The LA Galaxy against Chicago had 127 instances where a player was tackled and possession was lost.
Taken out of that figure are clearances by the other team where they were unable to maintain possession (so now 117 tackles where possession was lost) and then added in are a team's attempts on goal (the Galaxy had 14). That gives us 131 possessions.
Over on the Fire side they had 133 instances of tackles with possession lost with 8 unsuccessful clearances by the Galaxy. The Fire had 6 attempts on goal to give them the same131 possessions. Now Tempo-Free Soccer gives the LA-Chicago tilt an averaged out 129.5 possessions, so my math is wrong at some point but let's just keep running with it cause we're not that far off.
The Galaxy getting more than twice the amount of shot attempts out of their possessions than the Fire is certainly a good thing. With these figures one can do things like divide the number of passes by the number of possessions to see how many passes per possession a team manages. We get 3.7 passes per possession for the Galaxy and 2.8 for the Fire. Again, my numbers aren't lining up with Tempo-Free soccer, but the Galaxy seem to have managed one whole more pass per possession than the Fire. That's a good thing.
Tempo-Free Soccer has the Sounders and Timbers as the teams with the most passes per possession. Moving along in the categories we see that the Galaxy are atop the offensive stats, no surprise given they've scored more goals than any other team this season.
Anyhow, I'm gonna keep my eye on Tempo-Free Soccer, and hopefully I'll learn a thing or two from the data being churned out.