Arsenal's Home Clean Sheet Outlier
Just 4 of the last 21 League Matches at home have been a clean sheet, that is quite an outlier
There is some serious weirdness going on with Arsenal and their ability to keep clean sheets at home.
By basically any statistical measure Arsenal only having 4 clean sheets between last year and the start of this season looks very off.
This was the second-best team in the league last season. They had a good (but perhaps short of elite) defense. They conceded the second-fewest shots, the second-fewest shots on target, the third-fewest expected goals, and tired for the third-fewest goals allowed. To make things even weirder they had the second-fewest total clean sheets last season conceding 0 goals in 10 of 19 away games last season.
In these 21 matches, Arsenal have allowed less than 1.0 expected goals in 10 of those matches and have a clean sheet in just two of them. Using a match simulator for each shot’s xG in a match to get the simulated probability of the goal distribution Arsenal had 6 matches with greater than a 50% chance of keeping a clean sheet.
Taking these odds and then simulating the outcomes gets the following spread outcomes.
These simulations indicate that you would expect Arsenal to have kept a clean sheet in around 7 matches, +/- 2. Having 4 clean sheets is exactly correct in just 5% of the simulations, while it's a sign of underperforming in 93% of the simulations and a sign of overperforming in 2%. This is -2.1 mean absolute deviations from the expected mean.
In more basic language, this is a pretty big outlier for the performance.
Looking at post-shot xG instead tells a similar picture. Arsenal also have 10 matches where the post-shot xG is less than 1. They had 8 matches where the simulations gave them greater than 50% chance of keeping a clean sheet.
Taking these odds and then simulating the outcomes gets the following spread outcomes.
These simulations indicate that you would expect Arsenal to have kept a clean sheet in around 7 matches, +/- 1. Having 4 clean sheets is exactly correct in just 4% of the simulations, while it's a sign of underperforming in 95% of the simulations and a sign of overperforming in 1%. This is -2.4 mean absolute deviations from the expected mean.
Again, pretty big underperformance from what was expected.
At this point, with just 21 matches is hard to say if this is a systemic problem or simply bad luck. It is probably a bit of both. Arsenal have seemed to make a lot more sloppy errors and defensive execution lapses leading to a handful of big scoring opportunities while still managing to suppress shots and overall xG. It has not helped that the team has gifted goals in the opening minutes in 3 matches that they would probably have expected going into it, that they could keep a clean sheet. There is also some lingering questions about the shot-stopping ability of Aaron Ramsdale that this doesn’t help to quiet down (with a backup with a better reputation waiting behind him).
Hopefully, Arsenal can cut out some of these issues where they punish themselves and this becomes a moot point that doesn’t require a deeper investigation.
Champions League Draw Coverage
Adam had coverage of Arsenal’s group in the Champions League. It is worth your time to get up to speed on who Arsenal will face. It is good to be back on Tuesdays and Wednesdays.
Week 4 Match Odds
Friday is deadline day but there is also a match that feels like is getting second billing to everything else.
West Ham have won two big matches but will have a different test going into a match with an expectation that they will have some if not a majority of the possession.
The Saturday early match is an important early one for the relegation race. Everton badly needs the points here.
The 7am (3pm) kickoffs:
No close matchup here so for me I will probably turn on goal rush to watch the goals and exciting action and just take whatever the featured match is.
Both teams are coming off of an unexpected loss. Brighton because it was West Ham and they dominated possession but West Ham were not baited into leaving their shape and they couldn’t created clear chances. Newcastle got hit by Liverpool with 10 men and perhaps handed teams a blueprint of hand them the ball and see what happens. This match could answer some questions about these teams.
For Sunday I will probably start my day watching Aston Villa vs Liverpool. Unai Emery’s team has bounced back from their opening-day loss against Newcastle with big wins against Everton and Burnley. Liverpool have overcome being down to 10 men in their last two matches to move up to 7 points on the season. It will be really interesting to see these two teams match up.
The final match before we go into an international break is the one we care the most about here.
Lot’s of big questions for Arsenal’s lineup, who will be fit enough to start and the downstream effects from that. I don’t have any idea what it might be right now and it will continue to be interesting if Arteta makes it 4/4 on different starting lineups.