Bayern scored 122 in the Bundesliga last season. Record. The chances they created were worth about 92. That’s +30 on xG.
The usual read is regression. A gap that size almost never holds for a second year. If even half of it comes off and the rest of the table stays still, you get a title race instead of a parade.
The other read is that the model is describing the wrong thing. Bayern spend most weeks attacking a packed box. The shots look worse in the data than they do in the stadium because the defence is already on the six-yard line. Kane has also been beating his own xG for years, at Spurs and at Bayern. That’s either finishing the model can’t see, or a very long run of luck attached to one player.
That’s the bit I can’t land. Either xG is a decent map of chance quality and Bayern got away with something huge, or xG is a bad language for a side that creates the same kind of chance every week and has the same guy taking it.
I ran the season through Miroshark for a second pass. You give it the scenario and it stands up a room of stats people, scouts and fans and lets them argue, then bet. I didn’t want a prediction. I wanted to see if those two ways of reading the same facts would agree.
They didn’t. The talk side of the room was about 70% on someone other than Bayern finishing first. The betting side of the same room was basically 50/50. Same inputs, different posture.
It also used 100.9 xG for Bayern. The number is 91.9. So it was arguing for regression while shrinking the gap it was supposed to punish. That’s a sloppy version of something you see a lot: people treat xG like a moral scoreboard, then quietly change the input when the output feels too rude.
If you do believe the +30 comes off, you still need a side that can take the points. Leverkusen is the interesting one. Martínez wants them on the ball and Grimaldo is gone. Possession without the guy who used to break the press is a different team, even if the idea is the same.
Where do you sit?
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Give most of the +30 back. The model is fine.
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Give some back. Kane and the low block explain the rest.
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xG is just a bad description of what this Bayern side does.