Data analytics adds science to the valuation of footballers

How do you decide the value of a footballer? The problem has been given added torque by the vogue for applying data science to sports

Here is a data analytics puzzle. How do you accurately determine the value of a footballer? It’s a conundrum that has troubled football club owners for decades, and has been given added torque by the vogue for applying data science to sports. And it’s a debate that always intensifies at this time of year as the new football...

season looms and the transfer market hots up.

Historically, player valuation has been a far from scientific process, according to Paul Boanas, senior account manager at Prozone Sports.

“Clubs would completely rely on traditional scouting methods – the ‘eye test’ – without being able to bring objective information into the process,” says Boanas. “Very basic information, such as number of goals and assists, might have been used, and other considerations, such as contract status, commercial implications and biographical details (such as age) would come into play.”

How times have changed. Today, most clubs are “exhaustive in their pursuit of information about potential signings”, says Boanas, with performance data playing a vital role in this valuation process.

“Data enables clubs to engage in a far more rigorous and robust due diligence process, supplementing the intuition of scouts with objective performance information,” he says. “Where scouts may go to watch a player three or four times in person and arrive at an informed opinion, there is still the risk that they might have watched the player during a particularly good run of form that is at odds with their long-term form. 

“Prozone’s wealth of performance data enables clubs to assess a player’s performance over a far longer period of time, giving them a more accurate picture of the player’s on-field outputs and what might be expected of them if they were signed.”

Clubs can also use data to compare various transfer targets against each another and against players in the existing squad to come to a more accurate valuation of their worth based on their performances relative to similar players, says Boanas.

As well as using historical game data to assess a player’s value, some clubs are also starting to incorporate data taken from wearable technology devices to gain a more accurate insight, says Boden Westover, marketing manager at Australia-based wearable tech company Catapult Sports.

“Many of our teams put devices on players in pre-season to test them out and evaluate their worth,” says Westover. “Some teams will even send a device to a player they are keeping an eye on in another country and have their data synched with their team’s data to see where they rank.”

As the quality and breadth of data gathered by companies such as Catapult, Prozone and Opta continue to improve and evolve, clubs have a growing opportunity to drill even deeper into a player’s worth, says  John Coulson, Opta’s head of professional football services. 

“If we take goals, for example, as a measure for strikers, analytics can start to break down the value of the goals scored,” says Coulson. “Beyond the number itself, we can measure the importance of a goal, say in a 1-0 win or a 6-0 win. Then the strength of the opposition and the quality of the goal itself in terms of the difficulty of the strike and the impact of the goalkeeper, not least including whether it was a penalty or a goal from open play. 

“All of this analysis can give us a much better indication of the player’s goal-scoring ability than just the number of goals and we can apply the same process to all facets of performance, from passing to tackling, and create a much more detailed view of the player’s on-field value. Then, by looking at how these variables have changed in line with the player’s age and experience, we can start to estimate where the player is on their career curve and whether there is still room for improvement and an increase in value.”

Player marketability

Another increasingly important factor that clubs are adding to the valuation equation is potential commercial income – how marketable is a player to the club’s fan base and how much revenue might be derived from image rights and sponsorship deals?

All of this analysis can give us a much better indication of the player’s goal-scoring ability than just the number of goals and we can apply the same process to all facets of performance

John Coulson, Opta

Specialist London-based consultancy Orb Finance has devised a set of bespoke analytical tools and proprietary software to help professional football clubs take such factors into account when producing a valuation.

For instance, it estimated that Real Madrid would generate total profit of more than £41m over a six-year period from shirt sales related to the £85m signing of Gareth Bale from Spurs – an amount that would cover almost half his transfer fee. Orb also predicted that if Bale becomes as influential to Real Madrid as he was for Spurs in his final season at the club – recording an 11.6% team contribution score – then a transfer fee of as much as £94m would be justified.

The ability to produce statistics like these will doubtless ensure that data and analytics will play an increasingly important role in valuing players in future. But Coulson, for one, cautions that analytics can only take us so far.

“You still require the subjective assessment of a scout or coach to identify whether a player will fit into a particular team and thus justify a certain price,” says Coulson. “There are many off-field factors, such as the languages a player speaks, his ability to integrate with team mates and, perhaps most importantly, how coachable he is, can he be improved, and is he willing to learn? 

“All of these need to be factored in somewhere. Even medical records still require a subjective assessment. We cannot predict with certainty what injuries a player may suffer. We can only use the data to give us a guide and lower the risk in how we value the player.”

Or course, establishing a valuation of a player’s worth is just part of the total equation, says Coulson. The desire of both teams to buy or sell the player will ultimately be influenced by whether the teams compete with each other in the same tournaments, and perhaps also by the known financial budget of the buying team. 

So even though data and analytics might produce an accurate valuation of a player’s worth, what the buying club ends up spending could be vastly inflated by the peculiarities unique to the football transfer market.

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