Why Can’t Lukaku Stop Scoring ?

Recently, Romelu Lukaku scored his 100th career league goal, and his 50th goal for Everton, contributing to the end of a run of four league games without a win. But apart from his recent goalscoring form (7 goals in 10 apps),what makes me write a piece about Lukaku is the curiosity to analyse his numbers and trying to understand how his impressive attacking contribution has been built up throughout the years.

To do this, I would have liked to start with one of the most common and correct way to evaluate a striker performance that is the Expected Goals. But as I miss data before 2014 / 2015 season, in which Lukaku managed to score 15 (2013/2014) and 17 goals (2012/2013), I prefer to analyse things from other perspectives, trying to rely on more accessible data.

Shot Contribution

While looking for another way to evaluate striker performance, we should not fall into temptation to look only at players’ goals (that’s why we also have ExpG), as it is neither a good predictive metric nor a good way to compare different strikers. Using shot attempts has the value of giving us more events to analyze, which allows us to be more confident in the evaluation of a forward.

lukaku
Avg stats include players with more than 20 apps and more than 1.2 SoT p90

Keep in mind that I used a filter of players with more than 1.2 shots on target so that I can compare Lukaku to the best offensive players in the league.

As a reminder, green and red numbers do not correspond to good and bad performance; they just indicate whether Lukaku has performed above or under Premier League average.
For example, if we take total shots, it may seem Lukaku’s numbers aren’t that good. That could be true, but this metric accounts for all the shots taken by a player, irrespective of his shot position, which is something that matters and we will deal with this issue shortly.

Much more important are the values of shots on target and shot accuracy. A good striker, for the amount of shots he takes, should be able to put as much as he can between the sticks. Numbers tell us that Lukaku did this well. Also in his worst season, he didn’t come far from the average forward in the Premier League.

Shot Position

Let’s now continue with the concept of shot position that I introduced before. In effect, some shots are worth more than others. Some shots have a higher probability of being converted into goals whereas others have a much lower one. Therefore, a striker’s probability to score rises every time he shoots closer to the goal line. Then, what about Lukaku shot position?

shotLukaku’s Shots on Target Map (14/15 – 15/16)

These pictures confirm our theory. Despite Lukaku took identical amount of shots on target P90 in these two seasons (1.3 in 14/15 and 1.4 in 15/16), when shots are taken from more advanced position, goals are likely to come easier (yellow dots).

I’ve used Paul Riley‘s shot on target map here. This is because a shot map is way more appealing than a simple spreadsheet. But if we don’t have this kind of information, we can look for simpler data obtaining something that is obviously less comprehensive but still valid, like stats I’ve used in the first table, that are elaborated from WhoScored.

What’s next ?

As we have just seen, his four season goals streak could be explained by both his shot accuracy and shot position. These are two of the most important qualities for a top striker and Lukaku can definitively be included in this category.

Obviously, we are still missing a part of the full picture. These two metrics stand for creating goalscoring opportunities, but we are all aware that such a quality is a combined effort of both the striker himself and his team. Therefore, the influence of having good teammates is something we haven’t considered for the purpose of this article, but for a detailed and clear analysis it is crucial to get.

Finally, this was just a basic analysis to understand how Lukaku managed to score 15 goals on average in the last four seasons, but again, applying context to our numbers is something we should always do. Also, have a read to this brilliant article written by One Short Corner explaining “How (Not) To Use Stats“, with which I couldn’t agree more. I hope I’ve followed the basic steps provided there to get an easy but reliable analysis of one of the best Premier League strikers.

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