A belated letter to the Arsenal board
If you’re the type of person who is reading this article, then you’ll likely have noticed that, after an extremely brief period of rest and respite, football is back. Not actual football, of course, but the vital pre- pre-season, where clubs decide what direction they want to go in for the next year and, like an inhibition-less teenager, act on these desires.
Arsenal’s decision to keep Wenger on at the club (or, as it may have been, Arsène’s decision) seems like it was probably based on the strong finish to the season and FA Cup win. They did, of course, win 7 of the 8 games down the stretch when they played a 3-4-2-1, as well as the wins against Manchester City and Chelsea in the last two rounds of the Cup.
In terms of the league though, I regret to inform Mr. Wenger and Arsenal fans everywhere, in substance they were pretty much performing the same as they had done previously.
It’s important to note here that Arsenal is within touching distance of the rest of the top 6 on the offensive side of things, but there’s daylight between them on the defensive side. None of the rest of the Big Clubs concede more than 10 shots per game, nor more than 3-and-change shots on target.
You might have guessed it, but where things actually did change was in the conversion rates. For reference, before the table below, the average shot conversion rate is around 10-11%, give or take a couple of percentage points depending on if you’re a good team or not, while the shot on target conversion rate is around 30-33%.
Yeah, so Arsenal’s shots kept on being converted at normal levels, but their opponents started to score about half as many goals as might be expected (proper Expected Goals models are available elsewhere). It depends on how those goals would’ve fallen, but they could have easily resulted in at least a couple of results changing, dropping perhaps 4-6 points and moving a lot closer to 6th than 4th in the final table.
In fairness to the tactical switch itself, it did result in an improvement in the shots on target difference per game, up from +0.8 to +1.25, the only problem is that the rest of the Top 6 are all at +2.5 or above.
Fortunately, we can delve a bit deeper into the stats to focus on where they struggle. It’s similar to this article from Opta, though a lot simpler, but we can count all the things that end a spell of possession and call them (as Opta does) a ‘Sequence’. Doing this in the final third – with shots and defensive actions failed passes may be speculative and not quite what I’m looking for – can give you ‘Attacks’.
It’s an idea, albeit with slightly tweaked terminology, which I wrote about a couple of years ago here, though the numbers and percentages are slightly different in this season’s iteration (coincidentally, I used this to doubt Arsenal’s title chances in 2015/16).
Arsenal’s rates of converting Sequences into Attacks and Attacks into shots is roughly similar to the rest of the top 6 clubs (which is why their shot numbers are similar, of course). In terms of their defense, Arsenal’s opponents are turning Sequences into Attacks at a similar rate to some of the Top 6 sides: Chelsea and Manchester United are close; Tottenham, City, and Liverpool’s defenses are a little better.
However, all of these clubs limit their opponents to converting Attacks to shots at a rate of about 20-23%. For Arsenal, this rate has been 25.37% over the course of the whole season.
If you take each side’s Sequence -> Attack conversion (Sequence%) as a plus/minus, and do the same for Attack -> shots (Attack%), Arsenal are a noticeable handful of percentage points below their Top 6 rivals in both.
So while, on balance, Arsenal lag a little behind their rivals in getting the ball to the final third, and preventing their opponent from doing the same, it’s the balance of taking shots once the teams get there that’s the major issue.
[Sidenote: As for whether these higher rates are sustainable over a longer term or can be expected to repeat next year, the short answer is that I don’t know as I only have full data with this method for this season. My gut says that if they’re close enough to the average on each measure – attack and defense – it should be ok, and the fact that five of the Top 6 have similar rates suggests that they’re all reasonable.]
If you want a piece of trivia, West Ham has the Attack% rate in the league, just over 30% of their Attacks becoming shots – but they have the worst rate for getting their shots on target. Arsenal, meanwhile, has the worst rate in the league for their opponents’ shots being on target. This seems like a problem.
None of these issues outlined above improved in the 8-game stint under a 3-4-2-1. There were fewer Sequences per game (from around 345 per game down a little to around 310), but a similar amount of Attacks (just over 100, and then just over 98) with the distribution of these being shared in similar proportions between Arsenal and their opponents in both sections of the season.
To conclude, there really doesn’t seem to be a lot of meaningful substance which changed for Arsenal when they switched to the 3-4-2-1 in the league. If you’re reading this, Mr. Gazidis and Mr. Kroenke and co – as you wind down from the franticness of 2016/17 and start, finally, to think about the club going forward – I’d recommend allowing Arsène to walk out on a high. I’d certainly think very carefully about signing him to another two-year contra-
I should have sent this to the Arsenal board sooner.
*A note on how my version of Sequences and Attacks are created. Sequences are failed passes plus shots plus opposition successful tackles, interceptions, and clearances. Attacks are shots plus opposition successful tackles, interceptions, and clearances that take place within ~25 yards from goal (I do this by eye from StatsZone app, and use the second light green/third dark green as the cut-off line)
This article was written with the aid of StrataData, which is property of Stratagem Technologies. StrataData powers the StrataBet Sports Trading Platform, in addition to StrataBet Premium Recommendations.
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