Goals and assists are noisy and biased. They're credited to a single person when, in actuality, they're sometimes caused by other things. Often it's an exceptional pass from a teammate, but sometimes it's a fortuitous deflection or a dreaded goalkeeping howler.
And because a single season isn't a large enough sample size to glaze over extended sequences of good bounces, it's often impossible to identify the very best goalscorer or goal creator with complete certainty. That being said, it's fairly easy to narrow it down to a select few.
The newly crowned Volkswagen MLS MVP Robbie Keane belongs to that "few" after having a terrific season in both of these raw statistical categories. With 19 goals and nine direct assists (14 after including secondary assists), there were few players in MLS that were as intrinsic to their overall team's offensive production. However, breaking these raw numbers down into underlying metrics gives us a better understanding of just how exceptional Keane's season was. The industry-leading metric for underlying offensive production, commonly discussed in this series, is called Expected Goals or ExG.
Using Opta's touch-by-touch data set and ExG model, we're able to estimate the goalscoring likelihood of every Keane shot this season. All 122 of them. And by building these measurements into a Monte Carlo experiment that simulates a season's worth of Keane's shots 10,000 times, we're able to compare his actual goalscoring rate to what would be expected of an average MLS player if they were given the same opportunities at goal.
According to the simulation, Keane's 19 goals were the sixth-most likely goalscoring total given his scoring chances, and well above the most likely return of 16 goals. This really speaks to the pure volume of dangerous situations that Keane found himself in this season. Players near the top of a season's goalscoring table usually have near unrepeatable seasons with scoring totals they are unlikely to ever replicate. This has not been the case for Keane in 2014, and suggests that we may see more of the same in the post-Landon Donovan era.
By extending the Expected Goals metric, we also get a glimpse into Keane's direct assist total by applying the same model and mechanism to every one of his shot-assists in 2014.
These results tell a similar story. Keane's assist number is just about what you would have expected given the opportunities he directly created. What's really impressive is that he could have had a few more assists without it being an absurd string of fortune, because his attacking partners Donovan and Gyasi Zardes are multiple steps above the "average" MLS striker that this model assumes.
Without argument, Robbie Keane's season has been one for the record books. His 19 goals and 14 assists are stellar totals, and – most impressively – his steady and stable production wasn’t built upon large swaths of good fortune. Keane can realistically claim that his award-winning MLS campaign is repeatable – a luxury that hasn’t been afforded to many past MVP winners.