Expected Goals Model
Much of my modelling surrounds the topic of ‘expected goals’ and ‘expected assists’. Essentially, the models use historic data to go beyond basic goals and assists to find the true, long-term value of player actions.
Chance Creation Model
My chance creation model builds on the original SPAM model (below) by taking not only where the shot was taken from into account, but also how the ball was delivered to the attacker. Was he teed up from inside the box itself, from a cross out wide or from a long ball down the middle? In all, 30 different types of chance are accounted for including whether the final ball was from open play or a set piece.
The beauty of the Chance Creation Model is that it allows me to measure not just goalscorers on their shooting ability and decision making, but also the effectiveness of creative players within a team set-up. My piece on Juan Mata was featured on the OptaPro website.
After analysing over 30,000 English Premier League (EPL) shots over the last 3 seasons I was able to put a number on the average amount of shots it takes to score a goal from various positions on the pitch.
I called it the Shot Position Average Model (SPAM) and it was my first foray into football data. The OptaPro website has included SPAM in its showcase of the best in sports analytics writing from around the web.
I believe in simplicity. The graphic below shows the results of my study. This is how many shots it takes to score from these areas of the pitch in the EPL:
My study shows the numbers have been almost exactly the same in each of the last three seasons in each of these five areas:
- Direct Free Kicks
- Inside Box Central
- Inside Box Wide
- Outside Box Open Play
The sheer consistency of the model gives me the confidence to state that the benefit of having the specific x,y data so coveted would be outweighed by the loss in trying to practically apply it within the game itself, or inform the fans watching.
Within a year of SPAMs publication, the football analytics community had expanded rapidly to the point where today, similar principles are used in articles in The Guardian, the New Yorker and The Washington Post.