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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.

CCV, Zelalem, Klinsmann on U-20 roster as U.S. plays Germany, Netherlands, England

COMMERCE CITY, CO - OCTOBER 06:  Gedion Zelalem #16 of the United States controls the ball against Pedro Jeanine #5 of Panama during 2015 CONCACAF Olympic Qualifying at Dick's Sporting Goods Park on October 6, 2015 in Commerce City, Colorado. The United States defeated Panama 4-0.  (Photo by Doug Pensinger/Getty Images)
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In some ways, this tournament could be more interesting than the USMNT’s friendlies against Cuba and New Zealand.

The United States U-20 team is preparing for World Cup qualification by facing a fearsome threesome in the Four Nations Tournament in England.

[ MORE: PST talks with Michael Bradley ]

The Yanks will play Germany on Wednesday in Leigh, the Netherlands on Friday in Manchester, and England on Monday in Rochdale.

Among the names to watch, of course, are Spurs’ Cameron Carter-Vickers and Arsenal youngster Gedion Zelalem. Also, Jonathan Klinsmann, son of USMNT boss Jurgen, is one of two goalkeepers in the bunch.

A pair of Fulham players make the cut, as does new UD Las Palmas signing Emmanuel Sabbi. Seattle Sounders forward Victor Mansaray and Orlando defender Tommy Redding rep MLS on the roster.

[ MORE: Carter-Vickers signs extension with Spurs ]

It’ll be a must-follow tournament, considering the opposition. The Yanks will be tested by an English roster which includes Premier League players Reece Oxford (West Ham), Joshua Onomah (Spurs), and Lewis Cook (Bournemouth). England’s full roster is here.

U.S. U-20 roster

GOALKEEPERS: Jonathan Klinsmann (University of California), Justin Vom Steeg (Fortuna Dusseldorf)

DEFENDERS (8): Hugo Arellano (LA Galaxy), Marcello Borges (Michigan), Cameron Carter-Vickers (Tottenham Hotspur), Marlon Fossey (Fulham), Tommy Redding (Orlando City SC), Miles Robinson (Syracuse), Toni Suddoth (VfB Stuttgart), Auston Trusty (Bethlehem Steel FC)

MIDFIELDERS (7): Danny Acosta (Real Salt Lake), Luca De La Torre (Fulham), Derrick Jones (Bethlehem Steel FC), Brooks Lennon (Liverpool), Weston McKinnie (Schalke 04), Jonathan Suarez (Queretaro), Gedion Zelalem (Arsenal)

FORWARDS (5): Jeremy Ebobisse (Charleston Battery), Victor Mansaray (Seattle Sounders FC), Emmanuel Sabbi (UD Las Palmas), Sebastian Saucedo (Veracruz), Isaiah Young (PDA)

Jurgen Klopp angry despite Liverpool’s fourth-straight win

SWANSEA, WALES - OCTOBER 01:  Jurgen Klopp, Manager of Liverpool reacts  during the Premier League match between Swansea City and Liverpool at Liberty Stadium on October 1, 2016 in Swansea, Wales.  (Photo by Stu Forster/Getty Images)
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Jurgen Klopp‘s Liverpool ground out a 2-1 win at Swansea City on Saturday as the Reds have now won four-straight games in the Premier League.

Still, Klopp isn’t that happy.

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That’s because Liverpool were second best in the first half as they failed to cope with Swansea’s high-pressing and were behind 1-0 at half time.

Klopp had some strong words for his players in the dressing room and it worked as Roberto Firmino equalizes and James Milner‘s late spot kick won it.

Despite plenty of optimism over Liverpool’s strong start to the season — they have won five of their opening seven games and have 16 points on the board — the German coach wasn’t best pleased when speaking to Sky Sports afterwards.

“We are really happy in this moment, second half was like the whole game should have been. We were really angry with ourselves with the first half because the body language was not good and too late in mind and all that stuff. It was far away from our best performance but we showed a reaction in the second half and that’s important,” Klopp said. “You can lose football games and we will lose football games in the future but you have to show minimum part of your usual face. That’s what we showed second half and that was Liverpool and that’s what we think we should be. We were the deserved win in the end.”

Liverpool deserved to just edge the game but they could’ve been 2-0 or even 3-0 down at half time had Swansea been more clinical. Defending set pieces continues to be a problem for Klopp and his side have now conceded the most from those situations in the Premier League since he arrived last October. There was no surprise Leroy Fer‘s goal came from a set piece as zonal marking was again an issue for the Reds, while goalkeeper Lorus Karius looked a little nervy at times when coming for crosses as Mike Van der Hoorn should’ve equalized in the dying stages for Swansea.

With plenty of euphoria around Liverpool’s stellar start to this season, question marks over their defensive play still linger. Liverpool has now failed to keep a clean sheet in any of its last 10 Premier League away games dating back to last season, which is closing in on the club record of 12. Yes, we know they are the top-scoring team in the Premier League in 2016 but shoring up these defensive issues will be the priority for Klopp.

Klopp also confirmed that both Adam Lallana and Dejan Lovren are struggling with groin injuries. Lallana hobbled off in the first half and Klopp believes the England midfielder will not be available for Gareth Southgate over the international break.

“One or two problems today. Adam with a groin problem and Dejan Lovren too. I’m pretty sure they both cannot go now to national team,” Klopp confirmed. “We need further assessment and then we will see. Hopefully they can use the time to recover and be back in the race for the next game.”

Liverpool remain in the race for the PL title with yet another win but Klopp knows his side will come up against better opponents than a struggling Swansea and they got out of jail a little bit on Saturday.

STREAM: Watch Hull-Chelsea, West Ham-Boro, every 10am ET game

LONDON, ENGLAND - SEPTEMBER 24: Diego Costa of Chelsea shows his frustration during the Premier League match between Arsenal and Chelsea at the Emirates Stadium on September 24, 2016 in London, England.  (Photo by Paul Gilham/Getty Images)
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Four games take center stage at 10 a.m. ET in the Premier League on Saturday.

[ STREAM: Every PL game live here ]

Hull City host Chelsea at the KCOM Stadium, while struggling West Ham host Middlesbrough at the London Stadium.

Elsewhere Bournemouth head to Watford and Sunderland is hoping to get their first win as West Brom head to the Stadium of Light.

You can stream each game live by clicking on the links below or above.


10 a.m. ET: Hull City vs. Chelsea – NBCSN [STREAM]
10 a.m. ET: Sunderland vs. West Brom – Premier League Extratime [STREAM]
10 a.m. ET: West Ham vs. Middlesbrough – Premier League Extratime [STREAM]
10 a.m. ET: Watford vs. Bournemouth – Premier League Extratime [STREAM]

Pardew, Palace wish luck to FC Cincinnati; USL Playoffs underway (video)

CINCINNATI, OH - JULY 16: Tyler Polak #3 of FC Cincinnati steals the ball from Bakary Sako #26 of Crystal Palace FC as Paul Nicholson #8 of FC Cincinnati falls back on defense during the first half at Nippert Stadium on July 16, 2016 in Cincinnati, Ohio.(Photo by Kirk Irwin/Getty Images)
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Before Crystal Palace drew Everton 1-1 at Goodison Park on Friday, they turned their attention Stateside.

The club released a video message in support of United States third tier side FC Cincinnati on Friday, as the third-seeded USL club prepares to take on No. 6 Charleston Battery at Nippert Stadium on Sunday.

[ MORE: PST talks with Michael Bradley ]

Palace visited FC Cincinnati this summer, with 35,000-plus showing up as the Premier League side beat its USL opposition in a wonderful showcase for American soccer supporters.

Well, Pards and the boys were impressed, and issued a vote of good luck:

The playoffs are underway, with 16 of the 29 clubs making the march forward. Reigning champion Rochester Rhinos open up against Charlotte at Rhinos Stadium on Saturday, while the No. 1 seeds are New York Red Bulls II (Eastern Conference) and Sacramento Republic FC (Western Conference).

Full first round

Western Conference

Sacramento Republic (1) vs. Orange County Blues (8) — Saturday
Swope Park Rangers (4) 3-0 LA Galaxy II (5)
Colorado Springs Switchbacks (3) 1-2 Vancouver Whitecaps 2 (6)
Rio Grande Valley FC Toros (2) vs. Oklahoma City Energy FC (7)

Eastern Conference

New York Red Bulls (1) vs. Orlando City B (8) — Sunday
Rochester Rhinos (4) vs. Charlotte Independence (5) — Saturday
FC Cincinnati (3) vs. Charleston Battery (6) — Sunday
Louisville City FC (2) vs. Richmond Kickers (7) — Sunday