Barcelona's midfielder Xavi Hernandez re

Compromised numbers: Why the statistic you see may not be actual possession


One of the amazing statistics to come out of last Wednesday’s UEFA Champions League match was the possession number. Barcelona was reported by UEFA was having held the ball 72 percent of the time, an amazing figure against a club of Chelsea’s caliber. For those who have tried to find significance to correlations between possession and victories, the number must have been both remarkable and beguiling. After all, Barcelona lost, giving more credence to the hypothesis’ main qualm: What if one team doesn’t care about holding the ball?

The next day, the possession story got even more confusing. Supreme stat overlords Opta reported that Chelsea had only managed 20 percent of the ball. What? Even less time in possession? How freakish is this data point going to get?

That, however, is not the story. At least, it’s the story in light of what Graham MacAree notes at Chelsea fan site We Ain’t Got No History. As he’s found out, Opta seems to be miscalculating possession; or, better put, Opta is not reporting a number consistent with the normal expectation for a possession stat.

The normal expectation: When one team has the ball, they’re in possession. I think we can all agree on this, right? This still leaves a lot of gray area. For example, who gets credit for possession when midfield chaos leaves neither side in control? Does one team get possession on a goal kick, when most goal kicks lead to 50-50 midfield challenges? And more broadly, what happens when play is dead but the game clock is running?

I’ve always assumed this is like a chess clock. When one team controls the ball, you hit a button that sends their dials turning. When the other fully regains possession, you hit a button. One clock stops. The other starts running. Those in between moments? They’re governed by one rule: Until possession changes, don’t touch anything.

That, apparently has nothing to do with Opta’s calculations. In fact, Graham’s research suggests Opta doesn’t even run a clock, which may be why they never report possession in terms of time. Instead, the relation between reported possession and total passes suggests Opta just uses passes. As Graham found out, if you take a team’s pass attempts a divide it by the game’s total attempted passes, you have Opta’s possession stat.

What does this mean? Let’s take a totally fake scenario. Barcelona plays three quick passes before trying a through ball that rolls to Petr Cech. It all takes four seconds, while Petr Cech keeps the ball at his feet for eight seconds before picking it up, holding it for five seconds, then putting it out for a throw in, which takes eight more seconds to put back into play.

Despite Barcelona having possession for only four of those 25 fake seconds, they’d have 80 percent of Opta’s possession (three good passes plus one bad, while Chelsea had only Cech’s unsuccessful pass). A logical expectation of a zero-sum possession figure would have that as either 16 percent or (if you credit the time out of play as Barça’s, since they’d have the ensuing throw) 48 percent Barcelona’s. Or, if you do a three-stage model (that’s sometimes reported in Serie A matches), you’d have 16 percent Barcelona, 52 percent Chelsea, and 32 percent limbo/irrelevant.

Of the three methods of reporting possession, Opta’s bares the least resemblance to reality; or, it’s the one that deviates furthest from what we expect from a possession stat.

Ironies being a thing these days, there are two here. First, Opta is the unquestioned leader in soccer data management. How could this happen?

Second, Opta isn’t trying to hide their methods. In fact, they’ve published a post on their site detailing not only their practices but their motivations and research, an investigation that found their approach “came up with exactly the same figures (as time-based methods) on almost every occasion.”

You would think two curmudgeons like Graham and myself would have found this, right? Graham had a reader point it out to him, while a representative from Opta magnanimously pointed me to the piece without the seemingly necessarily indignation of explaining how a Google search works. After all Graham’s work and head scratching – after my lack of work and similar head-scratching – we could have just gone to Opta’s site.

“We try to be as transparent as possible with this stuff,” Opta said when I asked them about it. Certainly, they should be commended being so up front about their methods. After all, they’re a business that makes money off their work. They don’t need to give away their secrets.

But that’s a secondary issue. The main one: Why is a data house like Opta, reputed as the industry standard, taking this short cut? Or, why haven’t they renamed their measure? Granted, the perception that it is a shortcut may have more to do with our expectations than their intent, though based on their defense in the post, it’s clear they do see this as an accurate way of describing possession.

Still, the number they publish is completely redundant to the raw passing numbers also distributed. Why put the measure out at all if not to check a “possession stat” box on a list of deliverables?

Opta’s possession stat shouldn’t be cited in reporting, and if it is, the word “possession” shouldn’t be used to describe it. Reader expectations for anything labeled “possession” are drastically different than what Opta’s producing. The number is confusing to the point of being misleading. It’s becoming counter-information because of its poor packaging.

Even though Opta’s post on the topic is 14 months old, most will be surprised to hear this “news.” It’s disconcerting for anybody who is hoping a SABR-esque revolution’s on the horizon. Almost all of the huge volume of data to which we have access has been useful, but where people are expecting something akin to linear weights to be published tomorrow, we can’t even agree on the terms (let alone the significance of them).

Graham probably puts it better:

I’m completely fine with keeping track of passing volume – I’ve done it before myself. What’s frustrating, from an analyst’s point of view, is that we’re being sold a dud. A statistic that ostensibly measures possession measures something that is not possession, and gets repeated as authoritative anyway.

And people wonder why football statistics don’t get taken very seriously.

Conte: My Chelsea will never play for a draw, home or away

HULL, ENGLAND - OCTOBER 01:  Antonio Conte, Manager of Chelsea reacts to his team scoring during the Premier League match between Hull City and Chelsea at KCOM Stadium on October 1, 2016 in Hull, England.  (Photo by Laurence Griffiths/Getty Images)
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Antonio Conte knows what he’s doing — he’s playing the game made popular the world over by his predecessor and Sunday opponent, Jose Mourinho, and so many others who went before him.

[ MORE: All of PST’s PL coverage ]

Where other managers shy away from the controversy and the spotlight brought upon themselves by the psychological warfare waged by so many of the giants of the managerial profession, Conte has embraced the added attention he’ll now face when Chelsea host Manchester United on Sunday (Watch live, 11 a.m. ET, on NBCSN and online via

While Mourinho hasn’t been quiet in the build-up to his return to Stamford Bridge — how could he, given the considerable demand for comment? — he has mostly kept the cheap shots to himself and attempted to treat the affair like any other. Of course, it’s not that for him; for the Chelsea fans; for Chelsea owner Roman Abramovich, who made the decision to fire Mourinho 10 months ago; and now, for Conte, who’s suddenly thrust onto the other side of the battlefield ahead of Mourinho’s grudge match — quotes from

“No, I think it is always right to play for a win. I try to transfer these thoughts to my players always. If you play at home or away, it must be the same.

“You must start the game with only one target: to win. Not to play for a draw. I don’t like this. It is not football. I don’t like this.”

“I think it is important to win, but for me also, it is important to win in the right way. Because, sometimes, it happened to me. I won in the past with other clubs, but I wasn’t satisfied with the performance.

“When you win is important, but it is important to also play good football, to play with a good intensity, to show always the will to win, the passion. For me, that’s important.”

The obvious inference here is that Mourinho’s teams have always been set out to play in a defensive manner — often times aiming for, or, at the very least, achieving 0-0 draws — something the Portuguese did earlier this week, away to Liverpool.

[ MORE: Saturday’s PL roundup: Liverpool, Arsenal go joint-top ]

Conte didn’t ask to be the anti-Mourinho when he was named Chelsea’s new boss — not directly so, at least — but it comes as part of the territory when taking over from a mountain of a manager like Mourinho. Cool as ever, Conte is relishing his new role.

Introducing Zabivaka, Russia’s 2018 World Cup mascot

MOSCOW, RUSSIA - OCTOBER 21: Official Mascot Wolf was chosen as Official Mascot of FIFA 2018 World Cup Russia and Nazario Ronaldo during 'Vecherniy Urgant' (Evening Urgant) TV show on Channel 1 at Ostankino on October 21, 2016 in Moscow, Russia. (Photo by Getty Images/Getty Images)
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MOSCOW (AP) Russia has chosen a cocky wolf wearing sporty goggles as the mascot for the 2018 football World Cup.

The wolf was chosen in online voting over two other mascot candidates — a cat and a tiger wearing a space suit.

[ MORE: Saturday’s PL roundup: Liverpool, Arsenal go joint-top ]

The announcement was made early Saturday at the end of an hour-long broadcast on state Channel One television. More than 1 million Russians voted in the contest, according to the broadcast.

World Cup matches are to take place in 11 cities in June and July 2018. The venues are in Moscow, St. Petersburg, Kaliningrad, Kazan, Krasnodar, Rostov-on-Don, Samara, Saransk, Volgograd, Nizhny Novgorod and Yekaterinburg.

MOSCOW, RUSSIA - OCTOBER 21: (L-R) Wolf, the winer of FIFA 2018 World Cup Russia Official Mascot, Deputy Prime Minister of the Russian Federation Vitaly Mutko, TV host Ivan Urgant and Nazario Ronaldo attend at 'Vecherniy (Evening) Urgant' TV show on Channel 1 during at Ostankino on October 21, 2016 in Moscow, Russia. (Photo by Getty Images/Getty Images)
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Aguero looking vulnerable as Man City evolves under Guardiola

MANCHESTER, ENGLAND - OCTOBER 15:  Sergio Aguero of Manchester City shows dejection after the final whistle during the Premier League match between Manchester City and Everton at Etihad Stadium on October 15, 2016 in Manchester, England.  (Photo by Clive Brunskill/Getty Images)
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MANCHESTER, England (AP) Manchester City’s spine of goalkeeper Joe Hart, center back Vincent Kompany, midfielder Yaya Toure and striker Sergio Aguero has anchored the team since 2011 in the most decorated period in its history.

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One by one, it is being dismantled by Pep Guardiola.

Hart has been sent out on loan to Italy.

The injury-hampered Kompany no longer appears first choice.

Toure has been ostracized.

And the seemingly unthinkable is happening: Aguero is coming under pressure for his place.

Aguero started on the bench for the English Premier League game against Everton on Saturday after playing two matches for Argentina during the international break. More surprisingly, he stayed among the substitutes for the Champions League match at Barcelona on Wednesday, when Guardiola preferred to play midfielder Kevin De Bruyne up front.

[ MORE: Saturday’s PL roundup: Liverpool, Arsenal go joint-top ]

Aguero has been untouchable, a guaranteed starter since joining from Atletico Madrid in July 2011. Suddenly, possibly the most popular player among City fans – and a scorer of 102 league goals in his first five seasons at the club – is vulnerable and seemingly dispensable, even if he is likely to regain his place for the Premier League match against Southampton on Sunday.

When asked if Aguero was being phased out, Guardiola said on Friday the player’s future was at City.

“When Sergio decides to leave Manchester City, it will be his decision,” Guardiola said. Then, echoing comments he made about Hart in August before allowing him to leave, Guardiola added: “I appreciate him (as) a football player. I appreciate (as) a man what he did here.”

It’s not just the recent selection decisions that hint at a sense of unease between Guardiola and Aguero.

Guardiola has said publicly on at least two occasions this season that he wants more from Aguero than just goals, just like he wanted more from Hart than simply making saves. After Aguero’s hat trick in the Champions League win over Borussia Moenchengladbach, Guardiola said: “I cannot teach him (about his talent in the penalty box) but he has to know that behind, the rest of the team wants to help him and that is what I want to convince him.”

While on international duty with Argentina this month, Aguero was quoted as telling Argentine media that Guardiola “is very picky about everything, (and) it’s good.

“The good thing is that I’m getting used to him and automatically going straight into pressing the centre backs.”

[ MORE: Sunday’s PL preview — Mourinho back at the Bridge; City-Saints ]

Aguero, who is contracted to City until 2020, has 11 goals in 10 appearances this season, and 19 in his last 20 dating to last season. There are few better, attainable strikers around and it will be intriguing to see how the situation pans out, especially with Brazil forward Gabriel Jesus due to arrive in December to provide competition up front.

Guardiola said on Friday he had no regrets about his decision to drop Aguero for the Barcelona game, which City lost 4-0 after having goalkeeper Claudio Bravo red-carded. That made it four games without a win for Guardiola, and a failure to beat Southampton would equal the longest streak without a victory in his coaching career.

In an answer that lasted more than 6 1/2 minutes on Friday, he defended his tactics at Camp Nou and praised the personality of his young players like John Stones and De Bruyne.

Guardiola repeated he will not change his style.

“I think about that, yes,” he said. “But after that, the solution is not better than what I believe. So I cannot. Do you know why as well? Because in seven years (at Barcelona and Bayern Munich), I won 21 titles. … So it’s three titles per year playing in that way.

“No, no, I’m not going to change. First, it’s going to happen that (if) it’s not going well in the future, next season isn’t going well in that way, I will go home.”

La Liga & Serie A roundup: Messi wins it late for Barca; AC Milan shock Juve

VALENCIA, SPAIN - OCTOBER 22:  Lionel Messi of FC Barcelona celebrates with his team mates as Neymar Jr. and Luis Suarez reacts on the pitch after being hit by objects thrown from the seats after scoring his team's third from the penalty spot during the La Liga match between Valencia CF and FC Barcelona at Mestalla stadium on October 22, 2016 in Valencia, Spain.  (Photo by David Ramos/Getty Images)
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A roundup of Saturday’s action in Spain and Italy’s top flights…

[ MORE: Saturday’s PL roundup: Liverpool, Arsenal go joint-top ]

Valencia 2-3 Barcelona

Lionel Messi and Luis Suarez led Barcelona back from 2-1 down to take all three points at the Mestalla Stadium and reclaim the top spot in La Liga. There’s lots to unpack here, beginning with the nasty tackle that’ll keep Andres Iniesta (knee ligament damage) out of action for up to two months. Then there was the controversial fashion in which Messi gave Barca an early lead.

Valencia hit back twice before Suarez drew the visitors level again, and Messi converted from the penalty spot in the 93rd minute to seal the victory, at which point Neymar was hit by a bottle thrown onto the field by someone in the stands. In the end, Barca are back on top, until Real Madrid are allowed to have their say on Sunday.

Elsewhere in La Liga

Espanyol 3-3 Eibar
Real Sociedad 3-0 Alaves
Granada 0-0 Sporting Gijon

Sunday’s La Liga schedule

Celta Vigo vs. Deportivo La Coruña — 6 a.m. ET
Sevilla vs. Atletico Madrid — 10:15 a.m. ET
Malaga vs. Leganes — 12:30 p.m. ET
Villarreal vs. Las Palmas — 12:30 p.m. ET
Real Madrid vs. Athletic Bilbao — 2:45 p.m. ET

AC Milan 1-0 Juventus

The kids are (a whole lot more than) alright at AC Milan. 18-year-old midfielder Manuel Locatelli unleashed a stunning strike in the 65th minute, as Milan shocked the world by upsetting the five-time (and six-time, presumably) defending champions, Juventus, at the San Siro. Then it was 17-year-old goalkeeper Gianluigi Donnarumma’s turn to play his part, in the form of a stunning save to deny Sami Khedira an equalizer with the last kick of the game.

Juve remain top of the Serie A table, but it’s Milan who now sit second, just two points behind them.

Elsewhere in Serie A

Sampdoria 2-1 Genoa

Sunday’s Serie A schedule

Udinese vs. Pescara — 6:30 a.m. ET
Torino vs. Lazio — 9 a.m. ET
Atalanta vs. Inter Milan — 9 a.m. ET
Cagliari vs. Fiorentina — 9 a.m. ET
Crotone vs. Napoli — 9 a.m. ET
Empoli vs. Chievo — 9 a.m. ET
Bologna vs. Sassuoo — 12 p.m. ET
Roma vs. Palermo — 2:45 p.m. ET