Messi vs. Ronaldo: a goal-scoring comparison
With Cristiano Ronaldo and Lionel Messi both scoring their 41st goals of the season to break the La Liga all-time record, it seems like no better time to reflect on their remarkable records, even if the major honours are yet to be distributed this campaign.
The two men have scored goals relentlessly since Ronaldo’s arrival in Spain for the start of the 2009/10 season; Messi has 106 to his name, Ronaldo one more with 107.
The distribution of their goals has been notably similar too in the past three seasons. Both have scored 35 goals to give their teams the lead in games, while Ronaldo has marginally more goals as equalisers and for two-goal cushions.
The suggestion is that both players are as integral to their teams as each other. Neither player appears to inflate his goal tally on unimportant goals – something we can quantify using Soccer Statistically’s Outcome Probability Calculator.
By calculating a team’s chances of winning and drawing with and without a goal scored, we can get a sense of how many ‘expected points added’ a goal gives a team. For example, with the scores level in the 60th minute, a home team has a 33.7% chance of winning and a 44.7% chance of drawing. Their expected points – the number of points they would typically win from such a scenario – is therefore (0.337 x 3) + (0.447 x 1) = 1.458.
A goal increases the home team’s chances of winning to 81.4%, with a draw now at 15%, and expected points to 2.59, using the same method as above.
Therefore the expect points added (EPA) is 2.59 – 1.458 = 1.134, giving a sense of the ‘weight’ of the goal. Late goals that give a team a lead will clearly have more weight than late goals in a heavy win.
Adding up the total expected points added gives us total weight of goals from Barcelona and Real Madrid players in the last three seasons.
Despite a near-identical goal tally, Ronaldo’s EPA is marginally higher than Messi, which suggests he scores more important goals than the Argentinean on average. Above all though, the graph highlights the staggering contribution in goals from the two players.
To understand the average importance of each goal, we divide the EPA over goals to give the average goal weight (AGW).
Of the two clubs’ more prolific goal-scorers, Messi and Ronaldo lie near the bottom of the list; but there are reasons for this. The AGW metric penalises unimportant goals, bringing down a player’s average even if most of his goals add considerable expected points. Clearly Messi and Ronaldo fall into this bracket of players.
Central Winger shows that the average goal weight of different clubs may vary, which affects the AGW of players within that team. A team low on goals will, on average, score more important goals than a team who scores frequently. However, over the last three seasons Barcelona and Real Madrid’s AGW have been fairly similar, averaging around 0.52.
Players with a high AGW can be considered ‘clutch’ goal-scorers. Seydou Keita’s 10 league goals have come at an average weight of 0.73, well above both clubs’ average. However, this difference is insignificant.
It’s reasonable to expect players who score significantly more important goals (i.e. players who have high AGWs) to regress to the mean over time; it seems unrealistic for players to consistently score game-changing goals, particularly in teams like Barcelona and Real Madrid where scoring chances are abundant.
Yet over three seasons, Xavi has shown a surprising knack of scoring and creating big chances when it counts. By calculating the expected points added from both goals and assists, Xavi’s average contribution weight (ACW) is 0.67:
Although lower than Keita’s average goal weight, Xavi’s 42 goals and assists have been so consistently important that his average contribution weight is significantly higher than the average of all other players in the two teams. Is Xavi a clutch contributor? Perhaps. It may also be a result of him being subbed off after the ‘hard work’ is done, thereby denying him of the opportunity to deflate his average weight with unimportant contributions.
Ronaldo and Messi float around the average in this respect, and although Ronaldo’s AGW and ACW are greater than Messi’s, the difference is not large enough to suggest the Portuguese systematically scores more important goals. A full illustration of their importance can be found here, which shows that their EPA from goals and assists far exceeds their teammates’.
Their goal-scoring contribution is as prominent this season, with over 40% of both teams’ goals and total EPA. Again, Ronaldo appears to have scored more important goals – his EPA is higher despite identical goal tallies – but this difference is insignificant.
Of players with at least 3 league goals this season, only Fabregas and Sergio Ramos have higher average goal weights than Ronaldo. This is indicated by the chart above; both players have higher EPAs than their goal tally would suggest.
One of the key combinations this season has been Ronaldo and di Maria. The Argentinean has set up 6 goals for Ronaldo this season, with an EPA only bettered by Ronaldo’s total from the penalty spot. On the following charts, the first name denotes the scorer, the second name the assist-maker.
The chart above also highlights Ozil’s important assists for Ronaldo this season – three in total have added over three points in expectation. Messi’s big value added contributions have come when going solo; his three most prolific EPA combinations this season are unassisted goals, goals from penalties and goals from free kicks. Dani Alves may have assisted more Messi goals than anyone else, but largely these goals have not been important, indicated by a relatively low EPA.
Over the course of three seasons, similar patterns are repeated.
Curiously, Messi has only benefited from a Xavi assist five times in this period, all during the 2009/10 season. When they did combine however, it tended to be in big moments, with an average goal weight of 0.81.
Largely though, there are no major differences between the goal-scoring habits of Lionel Messi and Cristiano Ronaldo. Any differences in goal or contribution weights are statistically insignificant*. Both players score the proportion of important and unimportant goals that you’d expect – an inevitability rather than a criticism. Instead, it’s the sheer quantity of their contributions that is extraordinary.
EPAs calculated using Soccer Statistically’s Outcome Probability Calculator.
Assist data collected from football-lineups.com, and may not identically match alternative assist definitions.
More expected goal added posts are available on the Power of Goals blog by Mark Taylor, who kindly provided some guidance on interpreting EPA values.
*This was added on 18/04/12 to clear up any confusion.