Gladbach were the hot topic around the soccer stat Twittersphere last Friday as they were hammered by generally woeful Hamburg. This dropped the Foals to 4 games, 0 points, 2 goals for, 11 goals against and very much in last place in the Bundesliga. First some context as to why this blew up: Gladbach have had 3 very good seasons in succession despite posting average-to-really bad xG numbers. This chart should help tell the story. They had 3 of the 4 largest xGR outperformances in the past 3 seasons in Germany. I made the case in this article that they weren’t just a below-average team getting incredibly lucky, they were actually a good team being shorted by a model that didn’t cover what they did very well (mainly pressure opponents while shooting and then last season using a patient, multiple attack to get higher quality shots). The debate on twitter featured two StatsBomb legends coming out and basically saying Gladbach cannot beat xG long-term. Ben Pugsley said “Given enough time….barely any team is special” and Colin Trainor said it would be normal for some team to overperform xG 3 straight years given enough trials, which is true enough. Michael Caley hinted he thought the tactic had been collectively found out and that certain tactics could beat xG for a little bit before falling back to their underlying shot numbers. The 3-year run was over. In general the tone seemed to be, well this team has been lucky for so long, that now it is evening out. The insinuation being their true talent level during past seasons was reflected by the xG models and not the results on the field. I think in general this is a dangerous assumption to make and disagree in this case as well. xG hasn't nailed enough outliers for me to be confident in proclaiming teams drastically lucky or unlucky based only on xG rate. I disagree with Colin and Ben, both of whom I have great respect for. I do so knowing I might be wrong and willing to engage with anyone who wants to bring their case in the comments or on twitter. Let me lay my case out first. I don’t think this is a team simply playing as well as they always have been and midnight has finally struck. There are clear indicators that this year, the performance is significantly worse compared to years past. So even though it’s been 5 games*, I took a look at what has changed for Gladbach. *For me, 5 games is plenty to look at trends of how a team possesses and defends passes. Passing stats stabilize a lot quicker than shooting stats, so they can reveal trends quicker than shots/goals. If 1000 player minutes is enough to start making judgement calls on some player shot metrics, team pass metrics have now had nearly 5000 player minutes so should be able to tell us something. Offense The raw numbers show the offense is clearly worse, but some digging shows things are acutally even worse than a 2.5 drop in shots seems on the surface. Last year they were the best team in the Bundesliga when it came to completing passes in dangerous areas. They were 2 standard deviations above average in deep areas. This year that is not close to the case. Let's see why. They can’t get up the field A league worst 1.2% of Gladbach’s completions come in the Red Zone (within ~20 yards of opp goal). The league average is 3% and the Foals rate would easily be the worst single-season rate in the last 4 seasons in the Bundesliga if they keep it up. The problem intensified vs Sevilla as they had just 4 of their 353 completions in the Red Zone (1.1%). These completions are coming as a result of much longer passes as well. Last year their average pass distance for a Red Zone completion was the 2nd shortest in the Bundesliga at 14.1 yards, this year so far it has been the 3rd longest (behind only Ingolstadt and Darmstadt) at 21.6 yards. An increase of nearly 7 yards makes a significant difference in the amount of attempts you can expect to complete. So we see the problem, but where does it originate on the pitch? The Dortmund and Sevilla games were the largest hammerings and it seemed they couldn’t get out of their own half so I thought maybe they are just getting stuck close to their own goal. My eye test was not correct (a disappointingly common occurrence): Gladbach have moved into the opposition half slightly more often compared to last year. One possible problem this far from goal is that Xhaka has had to do way more offensive work in total and starts his work closer to goal as Stindl hasn’t quite replaced Kramer’s offensive production. Being so focused on one player to move the ball upfield doesn’t seem like it’s a great tendency for a team to have. But in the end, the Foals are getting the ball into the opposition half more often this year. They are getting the ball into the “attacking” area outside the box more often this year as well, even using shorter passes to do so. The big problem comes making the final leap, from the “attacking” area into the “opp box” area. Last year nearly twice as many completions were played into this area. It’s not a one-man problem when you see such a huge fall but the Max Kruse-sized hole shows up big-time here. Losing Kruse meant when Gladbach gets deep this year they need to rely on players who were not as good a passer as Kruse was like Hazard, Traore and Hahn (who graded atrociously last season). Now the ball gets close but doesn’t get into a dangerous area as often. No one has increased their load to pick up the slack. When you can’t get the ball deep, you can’t get the number of options needed forward that allows you to have a multifaceted attack. If you want to get open shots playing at a deliberate pace, it’s not going to happen as often with hoofing long balls to a single striker. Gladbach aren’t getting as many different players up the field. Players like Xhaka, Patrick Herrmann, and Raffael are simply possessing the ball much less close to goal. attempts here refers to passes Their extremely patient approach (.77 shots per pass attempt inside 20 yards last year) isn’t effective when you can’t get players forward and have the ball for long periods deep in opponent territory. They are now taking 1.13 shots per pass attempt, well above the league average. Defense Here the raw numbers look essentially similar but the block rate and distance per shot are certainly worrying. So what’s changed on defense? Worse closer to goal In my piece on them last year, I concluded that their strategy of conceding the middle of the pitch and focusing on congesting their own box led to forcing opponents into more harried shots than normal and cutting off passing lanes that could lead to a better shot. This is seen by the “Last 3 Seasons” bars in the chart below. Also in that chart, you see that there is no such effect this season. Essentially the Gladbach defense is basically as good stopping passes near the goal as they are the rest of the field, which makes it hard to conclude they are getting good pressure on shooters. (Final 12 and 13-25 are combined in this season to get a reasonable sample size) The Film Room After inferring decreasing close-to-goal pressure from these passing numbers, I wanted to check with my own eyes. I watched film of every shot from the 5 games so far this season to count Gladbach defenders in the box. I then did the same with the equivalent fixtures from last year (except subbing in Hertha for Hamburg and missing a few shots in the Mainz/Dortmund games, shots that weren’t important enough to make a thorough highlight reel). The clear-cut chances stood out in a big way. Last season in 33 charted open-play, in-box shots, zero came when Gladbach had fewer than 3 defenders inside the box. This season in 45 shots, 6 have already come with fewer than 3 defenders. 3 of those shots have been converted into goals. There were zero shots like this last season in the sample. It’s clear that the pressure they have always applied in the final 25 yards, increasing the closer you get to goal, is simply not there so far this season. Teams are passing very well in these areas and have broken through over once a game to take a shot against a basically abandoned box. Those are things that simply never happened last season. Now teams can spend more time picking and choosing their shots, which will certainly increase the chances of a goal. So while their raw shot numbers look about the same, under the surface there are massive problems. There are no individual defensive metrics I feel comfortable enough to divvy out the blame on this one. I will say losing Kramer, a sometime starter on the German national team cannot have helped. Fabian Johnson was injured in the opener and hasn’t returned. Maybe most importantly Martin Stranzl and Alvaro Dominguez, center-backs who started 41 combined games last season have both been out injured with Stranzl just returning for the last game. Replacing them have been mainly kids (19 and 20 year old started at center back vs Dortmund). That’s 4 key players from last years defense who have played 2 combined games this year. I don’t know how much that hurts, but it certainly is imaginable that a system like this is hard to simply plug and play at 4 key defensive positions. Conclusions Maybe Gladbach just didn't have enough talent to withstand the loss of stars like Max Kruse and Christoph Kramer. Maybe those two are way better than most people thought. Maybe this style of football is very precarious and when you downgrade certain parts, it all falls apart more quickly than other, more normal styles. Maybe things will totally turn around over the next two months. Any of those might be true. I can't say for sure, but what I do think is there has been enough in these 5 games to say Gladbach are playing much worse than they did last season. We aren't seeing a continued true talent level from last season with the only change being a correction in the luck category, there has been a significant performance drop. I certainly don't think I have completely explained everything about this drop above, soccer is much too complex a game to have supreme confidence about basically anything, much less something like this after just 5 games. Their performance will certainly change going forward but conclusions about xG in previous seasons should not be drawn from this team right now. They are not doing the things that pointed to xG outperformance. Gladbach were the team that kind of re-focused my energies away from fine-tuning a xG model and more toward looking at how teams pass and play on the entire field. Even if in a few months it turns out that proof emerges that xG was absolutely correct all along, I don't regret shifting focus. I have a clearer picture in my head of how Gladbach from looking deeper into passing stats, and I hope you do as well. Expected goals is a great stat and I love seeing the xG table compared to the regular table, but it's not always infallible and even when it turns out correct it's best use might be as a starting point to further investigation. I feel comfortable saying Gladbach over the past three years have shown us weaknesses in xG models and that's exciting to me. It means we haven't really solved how teams become good. The wide, wonderful world of excel spreadsheets, R consoles, and Tableau maps still has much to reveal.
Have Expected Goals Caught Up With Gladbach?
By admin | September 18, 2015