Revealed! How the Premier League table should REALLY look this season
If you hate the concept of expected goals (xG), we recommend you close this window now and get back to work. If you don’t understand xG but would like to know what the bloody hell we’re talking about, then that’s great. Just give this a read first.
One thing xG data can do is hint at which teams are over- or underperforming. It analyses the quality of shots taken by each side and, using tens of thousands of simulations, calculates a scoreline for how the match would finish if all things were equal – and by things, we mean players. It’s therefore possible to see how many goals a team ‘should’ score or concede, and consequently how many points they ‘should’ win across a season.
Now, ‘should’ is a loaded term. What xG and xGA (expected goals against) is really telling us is the average scoreline that we might expect from the particular goalscoring opportunities in a match; that doesn’t necessarily translate to calling a team lucky, unlucky or cursed by witches.
It can suggest that a team’s positive results are unsustainable. For instance, Reading’s xG performance in battling relegation from the Championship this season isn’t so different to their xG performance in reaching the play-off final last season, but their results reverted to the norm. However, the Royals weren’t hostages to fortune. It’s most likely that a side outperforming their xG score is being unusually clinical at one end and/or busy yet impenetrable at the other.
If a team is consistently winning games that xG and xGA values would have them draw or lose, then that will become evident in their xPts total.
“This match is a real 2.76-pointer”
xPts, as you’ve probably guessed, stands for expected points (although researching the accuracy of expected pints has been both enlightening and enjoyable). It shows how many points from wins, draws and defeats that an average team could expect to have gained, based on the shots they took and allowed each opponent to take.
So, when Manchester City beat West Ham 4-1 recently, their xPts score was 2.76 and the Hammers’ score was 0.15. That’s because the average number of points City took from the game across thousands upon thousands of simulations was 2.76 – i.e. they won most of the time – while their opponents rescued a draw or even a statistically unlikely win only when everything went their way in attack and defence (which happened in approximately one of every seven match simulations).
Using xPts, we can see where each club might be now in the Premier League table, if every result this season was in line with the balance of play.
It makes for interesting reading.
You may have noticed that Manchester United are sixth in this table. A total of 59xPts cuts them adrift of the top four and just one place higher than a team which, in real life, have half as many points as United. The Red Devils have gained a division-high 18 points – 18! – more than xG suggests they should. But why? Or how? Or simply: WTF?
Three questions, one answer: David de Gea. While Jose Mourinho’s team are clinical enough in attack to score 67 goals instead of the 57 forecasted by xG, the biggest difference is at the other end.
United have conceded 27 goals in 2017/18, only one more than the runaway champions across town, and yet the goalscoring opportunities they allow opponents would result in 41 conceded if they had a run-of-the-mill Premier League goalkeeper. That -14 difference between xGA and actual goals against is bettered only by the -16 of Nick Pope’s Burnley – more on them later – with no other team topping -5.
Again, it’s important to remember that this doesn’t mean Manchester United are lucky, unless the end of that sentence is ‘...to have a superb goalkeeper’. He’s a United player, not some random external force. Nor is his current rate of saving unsustainable: last season De Gea saved seven more goals than would normally be expected; in 2015/16 that number was six; in 2014/15, seven. He’s quite good.
No wonder the Spaniard has won United’s Player of the Year award in four of the past five seasons. And no wonder Mourinho has changed his mind since January 2017, when he referred to De Gea’s three consecutive awards under David Moyes and Louis van Gaal in saying: “I think when a goalkeeper is player of the season, it’s because something is wrong.” Right now, De Gea is keeping Mourinho in a job.
NEXT: This season's biggest culprit...