Bad Numbers

Simply placing the word “bad” before a dreary noun seemingly endows an intimidating edge, perfect for a Hollywood movie title; Santa, neighbours, teachers, moms, and even grandpa all get the formulaic comedy treatment. It’s Bad meaning bad-ass in a way that gets past the censor.

Three games into the season, if only there was a bad-ass metric to assess Premier League teams’ strength, to provide a distraction from a soporific International weekend. But, as luck plays such a significant part in football, 3 matches isn’t really long enough for it to even out. So drawing conclusions from simple stats like goals or points is risky – does an unexpectedly good start best compare with 2014/15 Leicester or 1974/75 Carlisle United*?

My favourite metric for short term assessment is shots on target (SOT) – simple, more frequent than goals, easy to understand, and a reasonably good indicator of future performance. The table below shows average SOT difference per game for each team’s 3 matches. I use this to make some (qualified) observations.

SOTdiff

This already looks to be shaping up as expected. In fact there’s a 67% correlation between SOT difference after 3 matches and full season points expected by the betting market before the season started (from Sporting Index points).

The success of Chelsea and Manchester United stands out. Chelsea appear to have awoken from their slumber of last season when they were conventionally bad, rather than bad-ass (other than Diego Costa, obviously, where both apply). Chelsea’s stats are somewhat skewed by ten shots on target to none conceded against Burnley – but even so they’re looking every bit the elite team that they pretended not to be last season.

And Manchester United now look bad in a bad-ass way – embodying the personality of their new manager and star striker. Like Chelsea, outshooting their opponents by an average of 5 shots on target per match, eschewing their attacking impotency of last season.

United’s bad neighbours from the Etihad frat house with their own new bad teacher have started well too. But one point of caution from the numbers; City have scored from 9 of their 15 shots on target – 60% is an unsustainably high conversion rate (long-term it’s usually around half this) and perhaps they’re not yet firing as smoothly as United and Chelsea.

Surprisingly, the team with the most shots on target so far are Everton with 22. Their start augurs well, with Koeman potentially performing the trick of curing Martinez’s bad defence, whilst maintaining attacking threat.

Last season Spurs posted spectacular shot numbers, consistently outshooting opponents by big margins. This season they’ve started slowly (they did last year too). Even so, they still managed more shots on target than their opponents against Liverpool – surprising from the evidence of watching the match. Teams with high shot numbers are often characterised by players that shoot all the time (with varying degrees of success). Both Spurs and Liverpool have players with this trait – particularly Kane and Coutinho. Although in the 3 matches so far Kane’s shooting output has been muted – not so for Coutinho, who already leads the league for shots, as he did last year.

Last season’s sensations Leicester City didn’t excel from a numbers point of view, rating only 5th using shots on target difference. But Bad Grandpa performed miracles to deliver the tactical robustness necessary to secure the title – it’s hardly surprising they’ve started slowly this season.

Of the newly promoted teams, Hull have confounded expectations – winning their first two and narrowly losing to Manchester United. But the numbers show that this is unlikely to be sustainable – 88% of shots on target against have been saved. Burnley memorably defeated Liverpool, but their underlying numbers (particularly SOT conceded) look shocking. Bad Santa Sean Dyche will need to deliver plenty of presents to avoid the drop. Boro have started steadily.

As said, drawing conclusions from three matches can be dangerous. However, early indications of long-term form change can be revealed. This is sometimes helpful for betting – but can also be risky. It’s all about applying good judgement; otherwise all we have is bad numbers.

The film industry shows us that when someone’s already appended “bad” to their chosen noun, then the next best alternative is “dirty”. This adjective also appropriately applies to much data used to analyse football – and, more importantly, teaches us that with the example of Robert De Niro (like Eden Hazard) even the best in the business can suffer sustained periods of underperformance.

 

*Carlisle famously (in 1974), in old First Division for the first time, topped the league after 3 matches – only to end up relegated in bottom place.

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