Thursday, August 28, 2014

The Rise of the "Technical Era"

This article originally appeared in Bloomberg Sports

If you watched Manchester City’s 3-1 victory over Liverpool earlier this week you would have been treated to a high level of football.  Both teams pinged the ball around in a desperate search for space, looking to score whilst simultaneously being wary of the opposing team’s counter-attack.  Possession was not conceded lightly.  Each team had approximately 100 turnovers and the average pass sequence per possession was approximately 5.7.  In short, the match was a far cry from the stereotypical long ball style traditionally associated with English football (note: only 8 of the 27 players featured in the match were English).  While just one match, this supremely technical style of play is indicative of a larger trend in the EPL.  Passes per game are up 20% since the 2009-2010 season, and a full 97% of that trend is attributable to the rise in the number of short passes.  Correspondingly, there has also been a drop in the number of turnovers committed.

These are very significant stylistic changes we are seeing in a relatively short period of time.  Out of curiosity, we looked at the other major leagues of Europe to see if this trend is particular to the EPL.  What we found is that the same exact trend is taking place all across Europe (and perhaps elsewhere).  In addition to the EPL, we looked at the Bundesliga, La Liga, Ligue 1, and Serie A (“The Big 5”).  Based on evidence of the first couple match days of this season in Europe, the rise of the “Technical Era” still seems to be in the ascent.  It will be worth watching where it leads us.

Monday, August 11, 2014

Ignore Geoff Cameron at CB at Your Peril

The consensus among most long-time observers of Geoff Cameron is that the American international is best-utilized as a central defender or, potentially, as a central defensive midfielder.  Not surprisingly, Cameron seems to agree with this assessment.  Most do not see Cameron as a natural right back.  And yet, that is where he has carved out a role for himself at Stoke.  Cameron made 36 of his 37 appearances in that role during the most recent EPL campaign.  While he performed ably, neither did he excel as he was unable to make full use of his athleticism— arguably Cameron’s best attribute.  But, there is growing speculation that other European teams see in Cameron what he sees in himself: an international-caliber center back.  The evidence, though not conclusive, indicates that Cameron should have no trouble finding a role in central defense for another team.

While we have a pretty good understanding of key performance indicators for attacking soccer players, there has been woefully little progress in measuring defensive players and, in particular, central defensive players.  This is understandable: the best attribute for a defender is the attacking play that did not happen – how do you measure that?  This major caveat aside, there is one measurable trait that most of the best central defenders possess— the ability to win aerials.  Opta measures both the # of aerials contested in a match and the % of these aerial battles “won” for every player.  Although he played as a right back, Cameron demonstrated an aerial prowess that compares well to his central defensive peers.

Skeptical that aerial win (%) means anything?  Here are the players with 70%+ aerial win.

We do have some more recent data on Cameron as a central defensive player.  We looked at his games vs. Turkey, Nigeria, Ghana, Portugal, and Belgium (he played as a central defensive midfielder this game).  We evaluated Cameron on three key central defensive indicators: aerial win (%), # of clearances, blocked shots (as a percent of shots conceded).  While not all-encompassing in their scope, these are some of the better indicators we have for center backs.  Here is how this admittedly small sample size of Cameron’s international work stacks up against the best center backs in the EPL (per composite rankings of Whoscored, Squawka, Castrol).  This analysis is in no way definitive, and you are no doubt thinking of that error vs. Portugal, but there is undoubtedly some compelling evidence on Geoff Cameron’s side.

Tuesday, July 15, 2014

The Best Uncapped American Player + MLS Homegrown Growth

With Jurgen Klinsmann looking to start a youth movement in the US national squad over the coming months we will no doubt see a slew of fresh faces earning their first cap.  And who do we want to see earn their first cap the most?  We have written about him before, but we have no qualms about doing it again.  Wil Trapp, the young Columbus Crew homegrown player, has been turning heads with his intelligent, technical play (see above pass distribution from a recent game vs. Colorado).

When looking at Trapp's statistical profile, one metric in particular jumps out: the number of 25+ yard passes he completes (what Opta calls "long balls").  Trapp completes an astonishing 9.8 of these per game, at a very accurate 86% clip.  The majority of these are not hopeful long balls to a striker, but are what most fans might call a "switching ball" that shifts the point of attack from one flank to the other - an indispensable skill for a holding midfielder.

While we know Trapp has a great statistical profile, it is difficult to really assess a player without surveying for potential comparisons.  As such, we looked at every central or holding midfielder under the age of 25 who completes 4+ 25 yard passes a game in eight top divisions: MLS, EPL, Bundesliga, Serie A, Ligue 1, Eredivisie, Russian PL, La Liga.  We found 22 such players (including the Whitecaps' Gershon Koffie and Matias Laba).  Then, we compared them across three major factors: pass distribution, defensive contribution, and pass usage rate.

There are a lot of familiar names on this list, including seven players who featured at the most recent World Cup, but it is self-evident that statistical comparisons across different teams and leagues make drawing any conclusions exceedingly difficult.  Each player is used in different tactical fashions by their teams and it is no doubt much easier for Wil Trapp to play a switching ball at home against Chivas USA than it would be for Jordan Henderson playing at Chelsea.  Nevertheless, it is hard but not notice that of the players who complete 6+ 25 yard passes a game, two played in the World Cup, two others play for their national team, a fifth is worth ~8M euros, and the sixth is Wil Trapp. Give the kid a cap, Jurgen.

MLS Homegrown Growth

Seeing the success of Trapp, DeAndre Yedlin, Diego Fagundez, and a litany of other MLS "homegrown" players, we cannot help but be excited about the future of the MLS academy program and what it portends for the league.  At the current rate teams are signing homegrown players (and if we assume an average MLS career of 5 years), it is not implausible that in 10 years over a third of the league will have been signed directly from an MLS academy.

Thursday, July 10, 2014

Ranking World Cup Rating Systems

Before the World Cup began we looked at what some rating systems predicted from the group stage.  To recap, the four rating systems we looked at were:

Elo: Originally devised as a method to rank world chess players, it is one of the most robust international soccer rating systems.
SPI: Developed for ESPN by famed political prognosticator Nate Silver.  
Oddsportal: An aggregator of 10+ online betting house odds.  Reflects the opinion of the betting public.
EA Sports FIFA Video Game: Based on player and team ratings provided by the popular video game franchise.

When we ran each system's match-by-match projections, certain geographical biases became noticeable (see below).

To re-iterate, we only looked at group stage games, and projected results were not modified as games were played.  In essence, the projections represent a "freeze frame" from before the World Cup began. Many other people have been tracking the rating systems, perhaps most notably Seth Burns over at Stats Bomb, who has been making "bets" following Nate Silver's SPI model.


Granted, the differences between each rating system might seem small, but don't be fooled. Over the course of 48 games (still a small sample size) it is significant that both Elo and SPI clearly outperform Oddsportal.  If you clicked on the Seth Burns link  you would see that by betting with SPI during the group stage you would have ended up over 600%!

Breaking the results down by region confirms what everyone knew watching the group stages:  the Americas came to play, while Asian teams were largely disappointing.

Tuesday, June 17, 2014

USMNT Fewest Passes per Possession (Klinsmann era 2011-)

The 10 fewest passes per possession  per game recorded during Jurgen Klinsmann's 49 game tenure.  You might notice that there are actually quite a few wins in the bunch, including the recent 2-1 World Cup victory over nemesis Ghana.

Thursday, June 12, 2014

Measuring Tactical Variance by League

This article originally appeared in Stats Bomb


Manchester City won the 2013-2014 Premier League with a diverse and international (and very expensive) squad.  Of the players who made 20 or more league appearances, a full eight different nationalities were represented (nine if you count their Chilean manager, Manuel Pellegrini).  Only one first choice squad player, goalkeeper Joe Hart, was English.
In many ways Manchester City is representative of what many see as the future of European football, one in which hyper cross-pollination of playing styles and tactics renders our old heuristics (Spain = tiki-taka, Italy = catenaccio , etc.) useless.  In this future world of European football, then, we might expect the distribution of formations/tactics to be fairly consistent across different leagues. Of course that is not the case now, and quite possibly will never be.
 In the complex world of game theory and football formations, sometimes it behooves a manager to stick with an unsuccessful setup for no better reason than it is what everyone else in the league is doing; many people do not like to take risks, especially if their job is on the line.  Conversely, in a league like Serie A where using different formations/tactics from game to game is almost an obsession, an adherence to one formation might be frowned upon.
 It should be stated that while this piece is about “tactical” variance our only measurement tool is “formation” variance.  Formations and tactics are not necessarily the same thing.  For example, a 3-5-2 might in practice more resemble a 5-3-2 and any formation can exist in an attack-minded or defensive form.  However, to the extent we are measuring tactical heterogeneity/homogeneity it seems self-evident that measuring formation variance is probably as good of a proxy as any.  Formation information comes from Opta, whose analysts watch every game for each team they are assigned.  Also noteworthy is this data does not include any in-game changes and is merely how each team lined up at the start of the game.  Information is from the last completed season (’13-’14) and includes only formations used more than 3%.  Formations are listed from left (most used) to right (least used).
formations by league
A couple things stand out here:
1. The Eredivisie loves the 433 and Russia loves the 4231, almost to the exclusion of any other formation.
2. Serie A demonstrates a tactical diversity not seen in other leagues (see below).
team avg formations
The “favored” and “unfavored” formations are partially a symptom of the fairly eclectic mix of leagues included in the analysis.  If we just aggregated all the teams from the “Big 4″ leagues (Bundesliga, EPL, La Liga, Serie A) this is what the results look like:
Big 4
The 4231 is certainly the fancied approach at the moment, but things can change.  For example, MLS has seen a rise in the use of the “diamond” 41212 in 2014. Unfortunately, this analysis does not include any data from previous seasons.  Will the homogeneity in the Dutch approach and heterogeneity in the Italian approach hold in the face football globalization?  It will certainly be worth watching.