Using Stats in Football – It’s Not a One-Size Fits All Approach

Football is my passion, my chance once (sometimes twice) a week where I get to shout and scream at the TV or stand up in the stands with 52,000 other just like me getting carried away with what’s on the field in front of us. Nobody bats an eyelid; nobody looks at you thinking you’re a madman. The only trouble with that is my job, my qualifications, all say I am a Performance Analyst – one of those people “ruining football” if you read the newspapers or listen to phone-ins.

Now, I have never worked in professional football as an analyst – I’ve always thought it would be difficult for me to reconcile my love of being at a game with the need to analyse every action that I see, stopping me getting emotional about what’s happening on the pitch and thus losing the joy of it all. So this, for me, is a big thing. I’m about to write about stats in football, why they matter and why I spend a lot of my time irritated and annoyed about the bastardised form of analysis the public have to swallow.

Obviously there are people who write a lot about this kind of stuff on the Internet, and do it brilliantly I might add. But nevertheless I feel the need to add to what’s out there by doing more than simply saying, “this is what they do”. Hopefully, I’ve given you a few other thoughts along the way as well.

Everyone seems to be writing about Leicester City at the moment, and why not? They’ve just completed a terrifically successful season and become the first new champions of the English top flight since Nottingham Forest. But how and, most importantly, why did this happen?

You’ll no doubt have heard they’re the team with the lowest percentage of possession to win the league – it’s all anyone goes on about. That, and their use of the “out-dated” 4-4-2 system, coupled with the “pre-historic” long balls they keep playing. Well, so what? Where does it say in the rules of football that the game has to be played in one specific, aesthetically pleasing, way? For me, it comes down to this – pundits, journalists, or “experts”, call them what you will – people don’t know how to use the numbers properly.

Luckily, I follow a more ‘enlightened’ bunch of people of twitter, and revel in their withering put downs of the partially informed.

Teams like Barcelona (2008-12), Bayern Munich (2014/15), Spain (2008-12), Germany (2013-present), Arsenal (Wenger era) all keep the ball, looking to stretch defences to move them out of position and rely on their ball control and passing ability to win matches. Their numbers for possession, total passes, passes completed, key passes, and through balls etc. are astronomical.

It must be that their way is the best way, surely?

Not for me. Yes, they’re magnificent teams that play the sort of football you’d happily pay obscene prices to watch – but that doesn’t mean they can’t be beaten. Inter Milan (2009/10) and Chelsea (2011/12) both beat Barcelona and went on to win the Champions League. Athletico Madrid (2011-present) keep achieving greater and greater things with every season and are in this years European Showpiece. These aren’t lucky teams in the same way you could say Leicester have been lucky (although I’d rather point out that they’ve been magnificent in their adherence to a game plan). They aren’t “cheating” their way to the top, as Bayern’s Vidal claimed, after they lost to Athletico’s brilliant performance.

To defend as magnificently as Athletico is just as skilful as the passing and movement of Barcelona, it’s just a different skill. To deride them as cheats, as lesser players, is to suggest that defending isn’t as important as attacking. Just ask Newcastle’s entertainers (the team I grew up watching as a child) if all out attack is always the best way? If it was, we’d have won the league in ‘96 and we probably wouldn’t be in the mess we are now with a second relegation from the Premier League confirmed. We played breath-taking, entertaining, joyous football but didn’t win the league. Would I have taken a few more 1-0’s and a few less 4-3’s to make sure that happened? Of course I would.

The way I see it is that most people are looking at the game the wrong way. Although that’s not to say I’m right either, I just have an opinion. As a Newcastle United fan, I’ve used some examples from the thumping 5-1 win vs Spurs on the last day of the season. It’s the only high point of a dreadful term, so I had to use it, didn’t I?

The matter at hand: to my way of thinking teams are only relevant to themselves, and their data is merely a snapshot in time to that specific team. A good example to think of is this: can you truly compare players from the 1950s to players today when the game is so different? You can take it to a player level too: is it right to compare Lionel Messi to Jamie Vardy? Well, you can try… but its apples and oranges, just look at the differences in radar charts of different styles of players in the same position (in fact, just read the whole thing – it’s excellent). They have different roles; they play in different teams, in different leagues and are light-years apart in terms of on the ball skill. But their effectiveness? That’s where they are similar – they both contribute hugely to the success of their teams.

Inter Milan, Chelsea, Athletico, Leicester et al., they all have one thing in common – they zigged when everyone else zagged. But they weren’t reinventing the wheel. They maximised the quality in their squads, recruited players that fitted into their system, had players that shared common goals and bought into a different way of playing that exploited their strengths. They didn’t try to be Barcelona, Bayern Munich, Spain, Arsenal or Germany – they realised they couldn’t be, and beat them all anyway.

What that means is that they used the data at their disposal properly.

An example of this is the mythical “Zone 14” – the section of the pitch highlighted below. To the untrained eye, it’s where the most effective passes come from – generally speaking, if you pass the ball from there into the penalty area you’re more likely to score goals. Historically the numbers say that passes from there lead to the most goals, so it must be the best yes?

Zone 14

My thoughts on Zone 14 are this – it’s a great place to pass from, if circumstances allow, but is most effective when you have two terrific wide players that stretch the defence wider than they want to be. Nowadays with analysts at every club, people know it’s the best place to pass from and defend differently (a la Leicester and Athletico) which makes the area much more condensed and difficult to break through. In doing this though, you can often lose sight of the most vital question analysts have to face: “so, how do you beat them?”

Well, the answer is obvious isn’t it? If you aren’t Barcelona, Bayern et al., but you have two fantastic crossers of the ball (either overlapping full backs or dynamic wingers), then get the ball into the space out wide; bring it to the byline and cross it in! Think of Arsenal vs Leicester this season – Arsenal got the ball wide and into space, crossed it in and caused mayhem. Giroud’s disallowed goal, Walcott’s equaliser, Welbeck’s winner (albeit from a free-kick) were all from crosses in the wide areas with an incredibly densely defended penalty area.

Arsenal vs Leicester

This has the double benefit of bringing Zone 14 back into play – because you’ll have executed the wide plays well, the defence will try and prevent the wide players getting the ball. This means there’s greater space to pass the ball into from Zone 14. BUT it’s difficult to manage, almost all analysts will tell you how difficult it is to create scoring chances when the ball is out wide – I think this has a lot to do with the use of inverted wingers, and a decreased importance placed on coaching players to cross the ball effectively.

Most number crunchers will say that crossing the ball is a fool’s errand, because it doesn’t often create chances (the average conversion rate is 1.76%) and is easier to defend against. But, that’s because none of the data currently available tells you why some of the leagues best players (Ozil, Silva, et al.,) encourage crossing from the very edge of the penalty area (think of someone like Zabaleta overlapping at pace, and crossing the ball low into the area between the six yard box and penalty spot).

Marek Kwiatkowski has an opinion as to why – to both paraphrase and elaborate: better teams won’t swing in the incredibly low percentage crosses that most analyst (including me) hate; they instead have a preference for low crosses into high quality shooting areas. Does this mean they’re not effective teams purely because they’re crossing the ball? No. What it means is they’re using their skill and technical ability to fashion better scoring opportunities for their colleagues than the average Premier League footballer. Moreover, it also doesn’t take into account where the ball ends up once a team ‘clears’ the ball – it could result in a corner, which you score from, or it falls to an attacking player who scores or assists because the cross led to a disorganised defence – these things may not be easily measured, but should definitely come into the conversation about whether or not crossing is a good/bad attacking ploy. The clips below show how a good cross can create a high quality chance, even if it isn’t directly scored from:

Good Cross 1

Good Cross 2

Alternatively, you beat the clogged up Zone 14 by never letting the opposition get into position. Again, something Leicester and Athletico do very well. Their use of the counter attack, and the long ball, are devastating because most teams nowadays only seem to be able to defend against pale imitations of ‘tiki taka’ football.

Griezmann Goal

One tactic relies on highly skilled players, the other relies on pace, directness, and a high percentage of shots on target from relatively few opportunities. This doesn’t mean to say that one is better than the other; it’s just a different way of combating new defensive structures. You need to tailor your analysis and your game plans to the players at your disposal – again, think back to the Messi vs Vardy comparison. If we’re going to get even more into the analysis, what about the effect of playing in the two ways I’ve just described?

Well, and huge thanks to statsbomb for being an incredible source of football knowledge, we know the most effective areas to score from (shown below using an expected goals (XG) method of evaluating shot quality). Luckily, Ted Knutson of recent Soccer AM fame (the author of the article I’ve linked to, and the source of the images below) is a clever bloke who understands the need for context and says “All shots in football are NOT equal” in an article about PDO. This is an important point to make when using XG data. Just because you shoot from an area that generally has a lower expected goals doesn’t mean it’s a bad thing to do. It also doesn’t mean that shooting from an area of higher expected goals is the best thing to do. It relies on context – and that you can get from video.

You could always include a subjective measurement of shot quality, or objectively include the number of players in between the shooter and the goal to augment the XG outcome; it would be time consuming I know, but surely someone at a Premier League club could do it for their own players if they didn’t fancy doing it for every team in the league? Luckily that’s for better analysts than I to sort out! To visualise this point, which of the shots below is of better quality taking into consideration the number of players in the way?

Screen Shot 2016-05-17 at 18.49.53

Anyway, the point remains that sometimes the numbers don’t tell the whole story. I remember reading a paper on Aussie Rules (a passion of mine after spending time living in the country playing cricket and studying), and they found that increasing the number of rebound 50s (a rebound 50 is when a defensive player moves the ball out of their defensive 50 metre area into midfield) had a negative correlation with points scored.

From a purely statistical point of view, doesn’t that mean teams should keep the ball in their defensive area to ensure they win? Well, obviously it doesn’t. It’s just an indicator of who was on top in the game – more rebound 50s = more time spent defending, thus less chance of winning the game. Anyone with even a foreigners understanding of the game can work that out. Scale that up and, while I think there are some wonderful bits of statistical research being completed within football, the true implications aren’t being reported – there’s something lost in translation.

I’ve always worked on the KISS principle – Keep It Simple, Stupid! But from a football watchers point of view, I don’t see many teams doing this. I see them getting lost, unable to work out how to beat these compact defences with the talent they have in their squad; devising plans that their players cannot possibly implement, but going for it anyway. I get the feeling that managers aren’t being told the meaning behind the numbers, just the numbers themselves and that isn’t good practice.

The numbers provide competitive edges and analysis department will only continue to increase in importance if used correctly; and if you want any more evidence from a much more well informed source – here’s a link to another great Ted Knutson article to help you.

To summarise, stats in football are great so long as the people using them know how to do it properly. If all you can tell people are the numbers, as opposed to how you apply them to the real footballing world, you may as well not bother doing the analysis at all. What I currently see as a “one size fits all” approach is not what’s needed to turn great numbers into great on-field results. It’s a coherent plan, with numbers used in conjunction with knowledge of football.

UPDATE – Not long after I posted this, another Ted Knutson piece was posted online; with this quote seeming to say exactly what I’m getting at (although it’s in reference to managers it’s still relevant):

“The big thing to take away from it is whether a particular coach fits the style of play your club wants to play and/or how your personnel might fit into their new style of play. If you have to bin half your squad simply by hiring a new head coach, maybe you want to look a bit closer at some other coaches whose style doesn’t require quite so much immediate, expensive change.

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