Traditional top scorers charts rank players simply by counting the number of goals scored, thereby assuming that every single goal scored has equal value. This goes against both emotional feeling and rational thinking. A late winner against superior oppositions ranks higher on both these scales than a goal that extends a dominating home team’s lead from four to five goals.
Explaining Win Points Added
During the summer break, we’ve looked into this subject, aiming to design a score based on Win Points Added, estimating the expected points won from a particular match and the difference a goal made to that value. This leads to all goals being valued between 0 and 2, with 0 for the goal extending a lead in a practically already won match, as it doesn’t add anything in terms of points won from that match, and 2 for the goal that turns a level game into a victory just at the final whistle, thereby turning the one points from a draw into the three points from a win.
The value for expected points won was derived from four parameters: opposition strength, venue, timing of the goal and, most importantly, goal differential before the goal was scored. The first two parameters, opposition strength and venue were derived from the average bookmaker odds for the game, while a formula for how these odds develop during the match, as well as the impact of goal differential was derived from the former www.whatifodds.com website. More details on the exact build-up of this system can be found in the original post introducing it.
Bony versus Mertens
One player sticks out far beyond the rest. The goals scored by Vitesse’s Wilfried Bony, six in total, have contributed to 4.52 points won for his team. While the average value of all 243 goals scored in the first eight rounds of Eredivisie matches is 0.49 points, Bony’s goals added 0.75 points per goal on average. This represents the fact that two of his goals were among the highest scores possible: a 2-1 winner in the 89th minute against Vitesse and the opening goal in the 88th minute against Heerenveen. Bony scored four of his six goals while the game was level, goals that are appreciated in this system.
In contrast, the conventional top scorer of the Eredivisie, PSV’s Dries Mertens, averaged only 0.18 points per goal, hence scoring a total of 1.97 points with 11 goals. Like Bony, Mertens also scored four goals while the game was level, but these goals were scored rather early in matches where PSV already had favourable odds of winning: Excelsior and RKC at home and ADO away. Mertens’ four goal at home against Roda, scored at goal differentials of 1,2,3 and 5 are excellent examples of goals that contribute very little in terms of win points added, but significantly bias a conventional goal scoring chart.
In the end
Ranking top scorers in terms of Win Points Added presents the impact of the goals scored, rather than the absolute number. This seems a better representation of the impact that these goals had on the ranking of teams in the league table. Players scoring goals that win games for their teams will top these kind of weighted scoring charts, representing the superior emotional and rational value of the goals they scored.
A .pdf version of the Eredivisie League Table and Weighted Top Scorer Chart is available by clicking here.