In the pantheon of advanced soccer statistics, "Expected Goals" is at the top of the heap, not just because of its predictive ability but also its power to illustrate. For a longer discussion on Expected Goals (or ExG), check out the latest MLS Insider (above) – but in short, ExG measures the likelihood of a shot resulting in a goal based on numerous factors weighted by their historical significance.
With Landon Donovan currently chasing Steve Ralston's all-time MLS assist record, it's appropriate to take ExG to an another level. Who has the most "Expected Assists" this season in MLS? Expected Assists, in its current form, piggybacks off Expected Goals by connecting each shot (and its corresponding ExG) to the pass that set it up – or as Opta calls them, "key" passes. For example, if Donovan passes the ball to Robbie Keane, who takes a shot that's expected to be a goal 50 percent of the time, Donovan is credited with 0.5 Expected Assists.
Below are the 2014 MLS Expected Assist leaders. Notice, the actual assist numbers for the top players outstrip their expected assist rates by a large margin. This is unsurprising as the family of "expected" soccer metrics all assume that the players involved are the league average. The players below, and many of the players they are passing to, are above average MLS players – some by a large margin.
In addition, plotting Expected Goals against Expected Assists provides a telling illustration of individual player styles. Which attackers are "shoot first" or "pass first?" In the chart below, take notice of the red line. Players above the line have more "Expected Goals" and players below the line have more "Expected Assists".*
* The reason more players are found above the line is simple – not all shots are assisted and therefore a season's total ExG will always be larger than it's ExA.
Take a closer look at Seattle's dynamic attacking pair. While neither Clint Dempsey or Obafemi Martins are leading the league in either ExG or ExA, their proficiency in both categories combined is only usurped by LA's Keane. Check out the All-Star duo tonight as they take on Real Salt Lake (and their own ExA outlier Javier Morales) on Friday night (10:30 pm ET; NBCSN and streamed on NBC Sports Live Extra in the US, TSN2 & RDS2 in Canada).