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

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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.

Klopp says, “This is my team now”; Does Sturridge Dance (video)

PASADENA, CA - JULY 27:  Liverpool manager Jurgen Klopp looks on prior to the start of the match against Chelsea during the 2016 International Champions Cup at Rose Bowl on July 27, 2016 in Pasadena, California.  (Photo by Jeff Gross/Getty Images)
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Make no mistake about it, Jurgen Klopp has his team at Anfield.

The Liverpool manager, 49, took over for Brendan Rodgers in January and made some encouraging strides given that he was left with players who weren’t all designed for his system.

[ MORE: Januzaj wants United exit ]

Enter Sadio Mane and Georginio Wijnaldum. Bring on Ragnar Klavan and Marko Grujic.

Enter Klopp’s squad, from Sky Sports:

“This is my squad now,” Klopp said. “After all the transfers…this time it is my team. There are probably no players here anymore I don’t want. There are no signings I didn’t want, we have not sold anyone I didn’t want to.”

“I’m not afraid of making decisions – it’s part of the job,” Klopp added. “I am happy with my team now – all I can say is we will be a challenger.

That “not sold anyone I didn’t want to” part sounds a bit like some sour grapes from Borussia Dortmund, where Klopp watched several of his best skip town.

On a lighter note, Klopp cut a rug for a group of young fans at Liverpool, and the Reds were good enough to film it for us.

“If you do it long enough, you can fly”. Head down for some classic, but ultimately very misleading, Klopp.

Report: Januzaj wants to leave Manchester United for good

SHANGHAI, CHINA - JULY 22: Adnan Januzaj of Manchester United competes for the ball during the International Champions Cup match between Manchester United and Borussia Dortmund at Shanghai Stadium on July 22, 2016 in Shanghai, China.  (Photo by Lintao Zhang/Getty Images)
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Adnan Januzaj wants to leave Old Trafford permanently.

The 21-year-old has one club goal since his breakout 2013-14 campaign, when he scored four times in the season that saw him turn 19.

[ RANIERI: Mahrez will stay at LCFC ]

It wasn’t long ago that the debate on Januzaj’s stardom was not hyped as if, rather when. Countries were fighting for his international future, and United fans were rankled when he didn’t hit the pitch.

Now, it’s a surprise if he factors at all. Januzaj hasn’t played for Belgium since 2014, and made just 12 appearances during a loan stint at Borussia Dortmund last season.

The Daily Mail reports that Januzaj has told Jose Mourinho he’s ready to leave Manchester.

Sunderland have been tipped as a possible destination for Januzaj, who certainly carries a lot of potential. The 6-foot winger has also been whispered as a target of Ajax and Milan.

WATCH: Neuer, Costa, Mourinho guest star in fantastic Pogba “Blah Blah Blah” ad

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Adidas has gone next level with its latest Paul Pogba advertisement.

Next level, or Talking Heads’ “Once In a Lifetime” video meets Kanye West’s “Power” (meets Tim and Eric).

The ad is extra pertinent as we wait to hear whether Pogba’s seemingly inevitable move away from Juventus for a record fee.

[ MORE: Transfer rumor roundup ]

Entitled “BLAH BLAH BLAH”, the advertisement features Diego Costa, Manuel Neuer, Thomas Muller, Jose Mourinho, Marcelo and others.

For me, the video is as instantly memorable as the “Take It To The Next Level” ad that shows a player going from Sunday league to superstar while Eagles of Death Metal’s “Don’t Speak” plays.

On another day, we can have a discussion on whether the Heidecker/Wareheim collective that brought us “Awesome Show” on Adult Swim is the most influential advertising inspiration in years.

Transfer rumor roundup: Welsh EURO stars to Everton, Sevilla, Atletico Madrid

LYON, FRANCE - JULY 05:  (Forward to back) Ashley Williams, James Collins, Jonathan Williams, Gareth Bale and Hal Robson-Kanu of Wales visit the Stade de Lyon, ahead of tomorrow's UEFA Euro Champs 2016 semi-final between Portugal and Wales, on July 5, 2016 in Lyon, France.  (Photo by Clive Rose/Getty Images)
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While much of the focus is on “will he/won’t he” when it comes to superstars like Riyad Mahrez and Paul Pogba, there are still plenty of fresh rumors going around the web this morning.

One of those involves a bit of a trend inspired by Juventus’ activity in the wake of Pogba rumors.

In the past, we’ve seen an almost dominant philosophy of investing in young players with the money gained from transfer sales.

[ MORE: Leicester lands Poland star ]

But Juventus prepared for a potential Pogba move by grabbing a fully-developed player who currently is an improvement on the Frenchman, nabbing Roma ace Miralem Pjanic.

Now Everton may be set to do the same thing. John Stones is by no means a finished product, and the Toffees may be forced into selling him to Manchester City.

Ashley Williams, at least right now, is a stronger player than Stones. The veteran Welsh defender leads both Wales and Swansea City, and would likely be a short-term step-up for Ronald Koeman‘s crew.

Wales Online says it would take $13 million to make the move happen, and with $50m coming in from Stones, that’s an easy decision (Though why would Swans sell? And Williams did support Liverpool as a kid).


Sky Sports says Paris Saint-Germain would love to see what Jese Rodriguez could do in a more demanding role. The Real Madrid man, 23, is jammed behind Cristiano Ronaldo, Gareth Bale and Karim Benzema at the Bernabeu.

From Sky:

“It’s a possibility, as are other opportunities in the transfer window,” Emery said during PSG’s tour of the US.

“I know Jese well, the club knows Jese well, he is a good player.”


Hal Robson-Kanu let his contract run out at Reading in the run-up to EURO 2016, when he scored what could be deemed the goal of the tournament.

That’s looking like a wise decision for the 27-year-old Welshman, who has become a target of Atletico Madrid and Sevilla in moves that would take him from England’s second tier to the UEFA Champions League.

Both sides are now for their signings being quite calculated, and Robson-Kanu carries risk; He hasn’t scored more than five goals in a season since 2012-13’s Premier League campaign with Reading.