Last week, with the help of Opta chalkboards, we explored the possibilities that arise when we are able to determine how likely a pass is to be successfully completed based upon key metrics such as pass distance, location and angle. Using this model, we were able to determine which players tend to complete passes that the average MLS player would not.
By approaching pass completion from this angle, we are liberated from meaninglessly looking at which player completes the highest percentage of his passes and begin to look at who completes difficult vs. easy passes. And, according to that analysis and model, I suggested that Dax McCarty of the New York Red Bulls has been the league's most effective passer.
Since last week, I have improved this model. While McCarty is still the bona fide league leader in pass effectiveness, the model now correctly predicts the outcome of 70 percent of all passes, up from 60 percent.
These improvements were made by compensating for things such as keeper throws, goal kicks and headed passes (which understandably increase or decrease the expected pass completion rate). Surprisingly, throw-ins were found to be almost exactly as effective as regular passes.
From here, we are going to look at all of the passes from this weekend's New England Revolution vs. Sporting Kansas City game, which resulted in a 0-0 draw.
But there’s a twist. We are not going to color-code each pass based upon whether or not it was completed, but instead color-code them according to how likely they were to be completed. Bright green lines represent passes that have a high percentage of being completed. As the color moves further along the spectrum toward dark red, the chance of completion drops correspondingly.
On the left is Sporting KC's graph. On the right, New England:
As one would expect, horizontal passes in the defensive third seem to be completed at a very high rate. On the other hand, steep crosses in the attacking third are completed at a very low rate. No surprises here – this doesn't suggest anything outside of common knowledge.
But, from looking at these two graphics, we can examine where teams tend to take more risks – and where they play more conservatively. Sporting Kansas City attempted a lot of high percentage passes on both of the attacking wings, which seem to quickly translate to more prospective crosses into the box. The Revolution seemed to be more inclined to attack more directly by probing balls into the center and right wing.
Since these graphics don't show if these dangerous or conservative passes were actually completed, it's very difficult to predict a winner from them. But, it does help visualize team tendencies better than looking at the meaningless binary stat of complete vs. incomplete passes.
Devin Pleuler is a computer science graduate from Wentworth Institute of Technology in Boston, where he played on the men's varsity team as a goalkeeper. He's certified as a coach through both the USSF and NSCAA, and writes the Central Winger analytics column for MLSsoccer.com.