One decision I made in constructing the Expecting Goals Team Ratings system was not to optimize just for the English Premier League. The training and testing set included equal numbers of seasons from the top divisions in Spain, Italy, Germany and France. It is possible that, at the margins, this decision will make the ratings and projections a little less precise for the Premier League. But it also means that for future studies, these methods have been tested on more data and can be used on a more expansive set of data.
And it means that while I covered the Premier League earlier this week, I still have a lot more Power Rankings to share.
La Liga Team Ratings and Power Rankings
La Liga table at FBRef for comparison
Glossary
If you want to see the method and explanation for these power rankings and how they were developed, that is in my earlier post this week, along with some proposals for future study.
Team Performance: This is a measure of how well the team has played in its matches this season, based on statistics that best project future quality, adjusted for red cards and opposition quality. It is expressed in goal difference per match. You can think of this as, how many goals better or worse than the average team has this club played over the season?
Attack Performance: This is the attacking component of Team Performance. How many goals better has this club’s attack been, compared to the average team, over the season so far?
Defense Performance: This is the defensive component of Team Performance. How many fewer goals and scoring chances has this club’s defense conceded, compared to the average team, over the season so far? Note that better defensive performances here are negative, in the sense that the team has conceded fewer chances and goals than average.
Schedule Difficulty: This is the opposition quality adjustment, also expressed in goal difference per match. A team with “+0.1” schedule difficulty has played a schedule which is harder than average by a margin of 0.1 goals per match. This measurement takes into account home field advantage and the team ratings estimated quality of opposition. A positive Schedule Difficulty reflects a harder schedule, in the sense that the team’s typical opponent is better than average.1
Team Rating: This is the current overall rating for this club, representing how my system will project their future performance. It is based on a weighted average of team performance combining goals and xG, regressed to estimated team value, and for promoted teams past performance is adjusted for league difficulty. Team Rating is scaled to 1.0, with 2.0 being a team that is roughly twice as good as the average team and 0.5 being a team that is roughly half as good as the average team.
Attack Rating: In the model itself, it is Attack and Defense Rating which are used to project matches. In the newsletter below I will get into the guts of what makes these up, but the basic components are what I listed under Team Rating. Like Team Rating, Attack Rating is scaled to 1.0, with 2.0 being an attack roughly twice as good as league average, and 0.5 half as good as league average.
Defense Rating: This is the defensive component of team rating. Note that while it is scaled to 1.0, now lower numbers are better. An 0.5 Defense Rating reflects a defense roughly twice as good as league average (that is, conceding half as many goals), and a 2.0 Defense Rating reflects a defense roughly half as good as league average.
La Liga Commentary
We covered La Liga in some detail on the most recent subscriber episode of the Double Pivot podcast, using these team ratings and our observations of the matches to break down the table.
Probably the most immediately striking there here is that while Real Madrid rate as the best team in Spain, Barcelona do not join them in that top tier so far. Barca have struggled with injuries, but also the defense has been conceding far too many good chances. It is very, very hard to win a title when you are conceding the sixth-most expected goals in the league. My system here rates their defense a little better than raw xG would suggest, both because there are two penalties in the xG total and because Barca have allowed only ten non-penalty goals, a more midtable total. So far these performances over nine matches have only dropped their Team Rating a little behind Madrid’s. Clearly there is time for a comeback.
Villarreal play Espanyol on November 8. I may regret it but I am planning to watch and the season data so far suggests it has a chance to be an entertaining match between two teams that have, at least so far this season, been playing good attacking football.
But the La Liga midtable really tells the story of Spanish football right now. The dominant tactical trend among sub-elite clubs is Getafe-style negative football, a style built on preventing opposition chances with a defensive approach that doesn’t rely so much on conceding opposition possession but on blowing up midfield with physicality, longballs and aerials, and driving down the percentage of live ball play in the match. It’s not great.
Serie A
As it has been for several years running, Serie A remains the most competitive top league in Europe. Inter have consistently had the best underlying numbers, but not by such large margins that the normal variation of soccer2 couldn’t allow Milan or Napoli to sneak in for a title. With Inter sitting third, three points behind Roma and Napoli, such drama may be on offer again in Italy.
If there was one thing most people agreed on before this Serie A season kicked off, it was that Atalanta losing longtime manager Gian Piero Gasperini to Roma would mean that Atalanta’s magic in developing attacking talent would leave for Roma as well, or perhaps that Gasperini had lost his touch and it wouldn’t work at Roma either. But somehow what has happened is that Atalanta remain one of the best teams in the league with a new breakout striker in Nikola Krstović and Roma have joined the ranks of Serie A’s leaders due to an elite defense, which is carrying a still sputtering attack. Football!
Promoted Cremonese are in eighth place now but with the second-worst expected goals difference in the league, and even this model which gives significant credit for goals scored has them among the worst sides in the league. It might be they have booked enough points to stay up but it looks fluky.
Generally the bottom of the table in Italy looks just as competitive as the top so there may be a dramatic relegation battle here as well.
Bundesliga
Bayern Munich’s 2.80 Team Rating is by a good margin the best of any team in the leagues covered here. At the same time, Bayern’s dominance over Germany is not new. Their Team Rating has run over 3.0 for periods in the last decade, in 2019 under Nico Kovač and earlier in 2017 under Carlo Ancelotti. During Pep Guardiola’s tenure between 2014 and 2015 the Team Rating almost never dropped below 3.0 and nearly touched 4.0. Bayern have unquestionably dominated the league so far but it will take even a higher level than this to match their modern heights.
It is striking that despite RB Leipzig running more or less even on Team Performance with Dortmund and Leverkusen, the model has not lifted their Team Rating up to a similar level. It is never clear to me what rate of updating is best, especially when a team has historically been competitive but has a terrible off year. Perhaps the club mean could incorporate a larger sample of past data. In any case, Leipzig’s negative expected goals difference last season will clearly take more time to filter out.
Gladbach have fallen all the way to last place and they rate among the bottom teams in the league across all metrics, but the one reed of hope is they have played the toughest schedule in the Bundesliga. On the other side of the coin are Stuttgart, who have played seven of their eight matches against teams in the bottom half of the table with the only exception being eighth-place FC Köln.
Ligue 1
The most striking thing here is not so much that PSG are not running away with the league — they have been rotating the squad in league matches with abandon and are still in first place with a perfect Champions League record as well. Rather, it is the apparent stratification of Ligue 1, a league more commonly marked by parity (PSG excluded) over the last decade. The top clubs are putting some distance between themselves and the rest of the table.
Marseille have played about one-third of all their league minutes either with a man advantage or disadvantage. They have a 24-11 goal difference overall but a 16-8 goal difference at even strength. This ends up not making too large a difference in Marseille’s overall team rating because of the way the red card adjustment is implemented, with a 40 percent credit or penalty to attacking and defending. Marseille creating about five xG and scoring eight goals while up a man over a few matches rates as such strong play, despite the favorable situation, that they still remain near the top of the ratings.
All underlying data from Opta unless otherwise noted.
There was an error here in Tuesday’s newsletter where I mixed up positive and negative. This is now fixed here and in the online version of the earlier newsletter. Positive schedule difficulty means stronger opponents.
To quote from my statement of purpose in the very first Expecting Goals newsletter.
One important editing note before we begin. I have written for British publications where I called the sport “football” and for American publications where I wrote “soccer.” They all had strict style sheets requiring that I could only use one or the other. But on my podcast I use the terms interchangeably, depending on my whim and the rhythms of the sentence. You can expect that to continue in the newsletter. Soccer and football are just two names for the same sport.