Patrician wrote:
My calculation for average chance of a clean sheet is...
Average xG conceded so far, then look up the chance of conceding zero goals using a Poisson distribution table.
How about the intangible one: how important is it to the manager/players to keep a CS?
You might think that it's always important but priorities are a shifting scale. Nuno apparently spent all last week in training working on compactness and defensive solidity and sent his team out last weekend with the primary aim of keeping a CS, even if they had to subdue their attacking instincts. It worked - basically they did a job on Bournemouth - but it meant that Doherty, for example, restrained himself from marauding forward (his average position was 10 yards deeper than usual and he didn't have a single goal attempt or create a single chance in the whole game). His sole attacking contribution was a single, solitary cross.
There are countless examples. The fabled Pulis CS machine was based on incessant defensive drills and shape drills to the point where the players could barely remember anything else and were in no doubt whatsoever that the CS was priority number 1. Allardyce similar and Burnley under Dyche similar. Usually those managers try to work on attacking fluidity based on that platform once it is established but if things go wrong (as at Burnley this season) they will retrench and go back to their defensive base platform as Dyche is doing now. I don't really care what xG Burnley have had so far this season; give me any sign that they are getting their basics back and it won't take much for me to bring Tarkowski or Mee in, in fact I am already thinking about it from GW19.
Then there are the top teams for whom defensive prowess is part of their DNA. It was a source of professional pride at Chelsea when JT was captain to keep a CS. Not just 'nice to do' but an important priority, even if they were 4-0 ahead. That, I think, is why City tend to win games well but concede 1 goal in doing so; the CS is less a source of pride to them than scoring a lot of goals is. Twice this season they have won 6-1; with another manager and a slightly different emphasis they might have won those games 4-0. They have the best defence in the PL but they probably don't prioritise the CS as much as many other teams do.
The last area I will mention is the gargantuan defensive performances a team threatened by relegation can sometimes produce if they get into a run. 'Big Dick' Advocaat did this with Sunderland a few seasons back; they basically defended their way to survival and every 45 minutes that went by without a goal conceded made them even more resolute. I remember them arriving at Stamford Bridge the game after they had secured their PL status; they were knackered and got thrashed 3-1 (and it could easily have been 6-1 to be honest). The prize had been achieved for them and they had nothing more to give. The large phallus balloons ('Big Dick') waved all afternoon in the Sunderland section just went to show how pleased the fans were with their team's efforts, although the Chelsea stewards seemed to think these were inappropriate and there were numerous funny occurrences of Sunderland fans wrestling with them over a giant phallus while the Chelsea fans sung "let them have their big dick back". Those are some of the best moments going to football.
Anyways...
how important is it to the manager/players to keep a CS? And also how important is it to the fans; do they relish their players throwing themselves into blocks and tackles (as at Burnley) or are they more the 'prawn sandwich' brigade who are mainly interested in seeing goals? Because the fans' attitude strengthens or weakens the intent of the players as well. Not anything you can put in a model but a significant factor nevertheless.