I have been working on an algorithm for striker ratings for a while now, but due to some difficulty finding data, the project was put on hold. Thankfully, after hours upon hours of searching, I finally stumbled across some numbers that proved essential to the process.
The algorithm spits out a rating that portrays how efficient a certain forward is in 90 minutes.
The chart below not only includes the final rankings but the other metrics I accounted for in the process.
First of all, it needs mentioning that these ‘Total’ grades are not out of a whole—meaning that Alex Lacazette did not obtain a score of .647 out of 1, but simply just a Total score of .647. The scores are made relative only to each other.
The total scores are obtained by five weighted metrics as well as two non-weighted stats. Despite the unique weights, each of the individual numbers is calculated roughly the same way. It starts by weighting each game individually based on the opponent’s defensive records. For example, Watford ‘s expected goals conceded per game is 0.7 (FiveThirtyEight), so therefore a single goal scored against them would be worth 1.25 goals (goals/expected conceded). In contrast, a goal against Fulham would be counted as .833 goals.
This is the same process used to determine the other four weighted metrics—adjusted assists/90, adj. key passes/90, adj shots on target/90, and adjusted shots per 90 minutes.
The two numbers that are not weighted by game are the player’s conversion percentage and pass completion rate.
Naturally, goals scored is weighted the most in comparison with the other numbers. Next are assists, key passes, shots on target, shots, and finally pass completion % and conversion rate.
The second and my preferred way of comparing the striker’s TES (total efficiency score) is by converting then to Z-Scores. Any stats guru understands the concept, but simply put, the Z-Score is the number of standard deviations away from the mean that a certain data point lies.
The idea shows how above or below average a certain player is. (*NOTE: The average is that of these seven forwards, not all those in the league.)
As you can see, City’s Aguero and Emery’s Aubameyang lead the pack with neck and neck Z-Scores (in terms of efficiency). Both Lacazette and Harry Kane are slightly above average. And Lukaku and Firmino’s season started relatively sub-par despite a recent rise in form.
Do remember that this is an efficiency rating, but it is not solely based off of goals. Even though Harry Kane’s goal tally of .803 goals per game, outdoes Aguero’s .779, Aguero’s other metrics such as passing stats and assists that push him just above Kane in the TES.
If I were to make a prediction about how this will look at the end of the season, my order would go as follows: