So we’ve turned our goalkeeping model about face to apply to strikers. Basically, we have split the penalty area and surrounds into 46 locations. We’ve then popped each of the last 11,000+ open-play shots on target from the last 3 and a half seasons into those 46 bins to give us an average conversion rate for each location for the Premier League. This gives us a benchmark to which we can compare each player. It’s called Shot on Target Position Average Model (SOTPAM). Oh yes.
We saw previously that mapping each teams shots on target (for and against) into these bins correlated over 80% with what was actually happening goal difference wise for the entire league. This suggests that ‘finishing’ ability itself isn’t the main difference between sides – merely that having more shots from better (closer, more central) locations is.
Does this hold for individual strikers too? It’s natural for most of us to assume that players like Wayne Rooney, Robin van Persie and the division’s latest goal-scoring sensation, Luis Suarez are simply much better finishers than their peers. Well using the model we can try and test this out.
For clarification, when we say ‘average player’ we’re really talking about a hybrid of mainly striker and some midfielder (they’re the ones who take the mass bulk of shots after all). So please don’t go thinking we mean you’re average lumbering centre back would get anywhere near the average number of goals we’re talking about.
A Luis, Roo or Bob shot on target doesn’t look much more accurate than any other forward’s. However………………………
What’s interesting with these players is that Van Persie and Rooney have quite a stable relationship with SOTPAM and actual goals. Suarez doesn’t. He was around 8 goals behind where he ‘should’ have been after about 40 games for Liverpool. He’s now 4 ahead after 99 games. During his Liverpool career Suarez has gradually reduced the quality of positions he’s shooting on target from while increasing volume:
Overall, it seems that if you want to score a lot of goals over time you simply have to take lots of shots (most strikers get 35%-45% of their shots on target over time). Suarez is now getting shots off at a rate that only Cristiano Ronaldo can beat and his underlying numbers have gone through the roof in Brendan Rodgers’ time at the club.
We are still left with the fact though, that his ‘finishing’ during his entire Liverpool career has been nothing special. What happens next? Yeah, still working on that one…
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