It is a metric at the heart of football’s fiercest culture war, pitting traditionalists against stat-savvy data experts. But expected goals (xG) – along with other analytics such as passes allowed per defensive action – has become a vital new weapon in the fight against match-fixing, the Guardian can reveal.
The Guardian has learned that there are more than 30 cases in over half a dozen countries where football analytics is being used in the package of supporting evidence – alongside suspicious betting patterns and intelligence – to bring those involved to justice.
In one major case, two teams are suspected of “trading” the results of their league and cup games, so that one club was saved from relegation and the other qualified for Europe. Although there were no unusual betting patterns, the authorities believed a fix was at play and went to experts at Stats Perform, which used its Opta data to identify several red flags. The matter is with the sport’s governing body and the police force in that country.
In another case, a team suspected of fixing the match had no touches in the opposition box, suggesting a lack of intent and triggering an alert. A third match under review involves a late goal from a near-post corner following a large number of suspicious bets on the number of goals in the game. Although on the surface nothing appeared wrong with the players’ actions, investigators used tracking data to show the defending team’s set-up and movements were completely different for the final corner.
Most sports bodies prefer not to comment on cases, and for legal and confidentiality reasons the Guardian is unable to name teams or countries involved. However Jakub Cavoj, the integrity officer at the Slovakia Football Association, confirmed it was among the federations using analytics in investigations.
“Performance analysis is an important new tool in the fight against match-fixing and is something the Slovak FA is starting to use,” he added. “We have to find new ways in how to support evidence and investigation of match-fixing and performance analysis can play an important role.”
Jake Marsh, the global head of integrity for Stats Perform, said it had begun to use Opta’s advanced analysis to support match-fixing investigations because suspicious betting patterns and intelligence were not always enough to bring a conviction.
“We started doing this about 18 months ago when a major football body said to us: ‘We’ve got excellent intelligence that indicates there has been a fix, but there’s been no spike in the betting markets,’” Marsh said. “‘We think significant amounts have been fed into the market in a way that has evaded detection. Is there a different way you can look for wrongdoing?’
“That led to us providing detailed reports on players and teams under suspicion – using measures like xG, supremacy, touches in the opposition box, tackle rates, and also passes per defensive action, which can show the lack of attacking intent – to help build a complete picture of a match. Usually we are not talking about slight anomalies but huge outliers in our database of thousands of games.
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“Of course xG isn’t the be-all and end-all. But if a team has a ton of shots from good positions but fails to score it might be a sign something is amiss. We also look at the team that’s under suspicion, and other matches they’ve played in the same competition, to see if we can find any anomalies in their style of play, tactics and intensity – along with conducting in-depth video analysis of the players and teams.”
Match-fixing cases can take at least 18 months to be resolved, and Marsh expects the first one with analytics as a key element to be concluded this year. “This isn’t the silver bullet for establishing that a match is fixed beyond doubt,” he said. “It’s not text messages, bank transfers or proof of money exchanging hands. But what we are often able to say is that the data corroborates intelligence that suggests a fix – and football’s authorities are telling us that it is incredibly useful.”
The Council of Europe, which in 2014 launched the Macolin Convention to promote global co-operation to tackle match-fixing, told the Guardian it was examining how analytics could be used.
“We have seen first-hand how performance analysis can be used to detect and investigate instances of match manipulation,” Elda Moreno, head of sport values at the Council of Europe, said. “We expect it to become part of the sport integrity fabric which supports the implementation of the Macolin Convention.”