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Expected Goals and Why they Matter

Expected goals and how they can add more objectivity to football.

Alexander Hassenstein/Getty Images

In what was set to be one of the most exciting games of Euro 2016, Croatia and Portugal played out an insipid 1-0 in the primary stage of the knockout phase. The match wasn't decided until the 117th minute and despite the somewhat 'surprise' result, the backlash and reaction from members of the media are what has seemingly garnered more attention within the footballing community.

Portugal, thanks to the newly implemented rules regarding group qualification, miraculously qualified for the knockout stages of this summer's competition as the third-place team. After failing to impress against the likes of international minnows Iceland, Hungary, and Austria, nobody expected much from a Seleçao team that certainly didn't represent a peak generation, but one that was still brimming with quality. Croatia, however, came into the tournament as a team with a bevy of high fidelity players, but, unlike Portugal, they didn't disappoint. Winning a group that featured Spain, Turkey, and the Czech Republic, despite their fans trying to get them kicked out of the tournament, the Croatians seemed relatively lucky to be drawn against a Portugal team that didn't win a game in the group stage.

The game that ensued was a tactical chess match that saw Croatia close off any opportunities for Portugal to break, while simultaneously failing to create very many solid chances for themselves. The quality of Croatia's performance is where the discrepancy in the community lies. Many fans and pundits, along with a few Croatian players, claimed that 'the better team lost,' and there seemed to be a palpable feeling that the result was an upset because of the notion that Croatia supposedly 'dominated' the game. The use of inverted commas should portray a sense of sarcasm because when you look at the in-depth metric, expected goals, it was a relatively balanced game. What are expected goals, or xG, you may ask? Well, you can find out more information on the specifics of what is it is here, but many experts in the community agree that in-depth metrics like expected goals, give us a better understanding of actual performance, especially when used in a retrogatory fashion. (I understand "retrogatory" isn't formally a word, but give me some bonus points for making one up to suit my cause)

The name 'expected goals' carries a certain connotation that it intends to predict how many goals a team should score given past information, and some xG models attempt to do exactly that, but looking at xG maps and data after the match can be extremely beneficial in terms of discerning whether a team just got lucky or were actually quite good. Enter Portugal v Croatia. As stated before, many seemed to have the impression that the Croat's dominated the game and 'deserved' to win, yet, they had almost the same xG rating as the Portuguese who registered eleven fewer shots on goal.

Though the Croatians dominated possession, 59% to be exact, they didn't do much with it. After fourteen shots with only one hitting the post, they failed to register any actual shots on goal. Possession without dangerous incision is useless, and should not be described as dominant. The following is an xG map of the shots that occurred throughout the game thanks to one of the leaders in all things xG, and fellow SBNation guy, Michael Caley.

The map clearly illustrates that although Croatia had more shots, they failed to legitimately threaten the opposition's goal. Perhaps a better definition of a domineering performance is needed, being that they only dominated possession, but this still does not excuse people saying that 'the better team lost.' Had Croatia registered more than zero shots on target then perhaps the insinuation that they were the better team might carry more weight, but it doesn't.

Now, I'm not suggesting xG is the end-all-be-all of statistics. It has flaws as Mr. Caley expressed in the article linked, but it is a tool that we can all use to be a more informed and intelligent group of journalist, analysts, fans, etc. .The cool thing about it is that anyone can make arguments for their specific viewpoint with more objectivity, and that's the ultimate goal, right? Objectivity.

So as we move forward into this new season with Pep Guardiola at the helm, I urge you to be more objective in your analysis of your favorite team. After all, via some insider information from Gabrielle Marcotti, the higher ups at Bayern Munich allowed for xG to decide whether they saw Guardiola's time in Bavaria as a success or not, and if it's good enough for them, maybe you should give it a whirl.