Possession in football consists of two things: first, to touch the ball and second, to keep touching it. Also, there are two qualities to possession: how many times a team gets the chance to move the ball, and the time length teams end up having the opportunity to move the ball.
The most straightforward way to calculate the number of possessions is to add up the number of times a team loses the ball to an opponent during the match. In the average American football game, each team averages about 11.5 spells of possessions, with the number usually between 11 and 13. This means teams turn the ball over about 23 times per NFL game, and between them they have 23 opportunities to do something positive with the ball. (Steelers Win Four in a Row!)
In basketball, the sport of abundant shooting and scoring, the number of possessions and turnovers is much higher – about ten times as high. In the typical NBA season, teams average between 91 and 100 possessions per game: a total of between 180 and 200 for both sides combined. (Introduction to basketball models and metrics)
In football, we need to decide on what a single possession is and how to calculate it. Let’s consider the high end of control: those times when a player wins the ball and the team then makes at least two consecutive passes or takes a shot. Opta sports collects such a stat to denote teams winning controlled possessions, though their term for team is “recovery”. Based on Opta data, teams gained possession in this way about 100 times in a typical match, for a match total of around 200.
If we define possession changes more loosely and include all the times when the ball changes from one team to the other, giving one team the chance to create something, the picture changes considerably and football looks even more inefficient. Including all those instances when the ball is intercepted, a player is tackled and loses the ball, fouls are conceded, shots go off target or the ball is passed straight to an opponent, the number of turnovers almost doubles.
In the average Premier League match, 10 of the 100 defined possessions yield a shot on goal and 1.3 in 100 possessions yield a goal. If we use the looser definition of turnovers and possessions, 6 in 100 loose “possessions” yield a shot on goal, and 0.74 in 100 of these actually yield a goal. Football is not a possession sport. It is a game of managing constant turnovers. (by turnover we mean loss of possession due to a mistake or poor control.)
In fact, there’s relatively little difference across clubs, regardless of whether they have a philosophy of playing “possession football”. In the Premier league, the top 10 clubs allow their opponents on average 101.4 strict possessions and 187.9 loose ones per match, while the clubs ranked eleven to twenty gave up essentially identical 99.1 and 189.3 possessions. So possession in Football is plural. The typical Premier League side has almost 200 fresh opportunities every match to do something with the ball. Most of the time whoever has it tries to pass it. The single most common action players perform are passes in all shapes and sizes: short, long, with the head or foot, crosses, goal kicks, flick-ons, lay-offs – passes account for well over 80 per cent of events on the pitch. The next largest categories of ball events, at 2% or less each, are shots, goals, free kicks, dribbles and saves. We can say that possession is turnover-free passing.
This also means that possession requires a collective, rather than individual, effort. It is a measure of team competence, not a specific player’s brilliance. Jaeson Rosenfeld analyzed relevant data as he was interested in working out how much a player’s pass competition percentage is determined by skill – something the player has control over – rather than the situation he finds himself in when making a pass. Rosenfeld’s hunch was that pass completion percentage had less to do with the foot skill of passing the ball and more to do with the difficulty of a pass the player was attempting in the first place. The analysis he made was on 100k passes from Brazilian Seria A league. To assess a player’s passing skill, he had to adjust pass completion by the difficulty of the pass being attempted. Passes in the final third of the field and under defensive pressure were more difficult than passes between two central defenders with no opponent in sight. Once he had taken into account things like pass distance, defensive pressure, where on the field the pass was attempted, in what direction (forward or not), and how( in the air, by head, and one touch), a curious result emerged: the skill in executing a pass is almost equal across all players and teams, as pass difficulty and pass completion percentage is nearly completely correlated. So it is virtually impossible to differentiate among players’ passing skills when it comes to executing any given pass. Everyone can complete a pass and avoid a turnover in an advantageous position on the pitch if they are without pressure or playing the ball over only a short distance. AS a result, at the elite level, the particular situation the passer finds himself in, determines a player’s completion percentage, not his foot skills.
Possession football is more than just being able to pass the ball – it is mostly about being in the right place to receive it, helping a teammate position himself in the right place in the right way, and helping him get rid of the ball in order to maintain control for the team.
A good team, when further up the pitch, manages to create a space for both the passer of the ball and his intended target, making the passing situation easier.
A poor team, in the same place, would not create as much space, so the passing situation would be harder. Good teams are not better at passing than bad ones. They simply engineer more easy passes in better locations, and therefore limit their turnovers. But pass volume and competition percentage aren’t equally useful indicators when it comes to predicting turnovers and repossessions. While those teams that complete passes at higher rate are less likely to giving the ball back to the opposition, pass volume – how many times a team passes – is only tangentially related to how often the ball is turned over.
The teams which don’t concede turnovers, which don’t give the ball back to the opposition as much, are the ones that can play good football in the middle of the pitch. They can pass more safely around their opponents. They are not necessarily the ones who pass the most. Volume of passing is a tactical decision. The rate at which passes find their man is the true indicator of possession quality, and that completion rate is less about the passing skill than about the shared coordination of passer and receiver to create simple connections in difficult locations.
Possession is related to success, not because of specific strategies related to what the score in the game was, but because of teams’ relative skill levels. Possession is about ability, and that ability is chiefly to create easy passing situations where others would be pressured and face narrow windows. And that means that, over the course of a season, those teams who prefer possession play and know how to achieve it successfully – will win out. In other words, teams who do a better job of keeping the ball away from their opponents do have more shots and do score more goals. In defense, they restrict their opponents to fewer attempts and they concede fewer goals. They have more shots on goal and suffer fewer. This, naturally, has a significant impact on goal production and goal prevention: teams that pass the ball well outscore their opponents by 1.44 to 1.19 goals per game, and they outperform them by an almost identical margin defensively.
When we turn to the other kind of possession – not turning over the ball – we see equally important effects. Teams that turned the ball over less than the other side outscored their opponents by roughly 1.5 goals to 1.1; they outperformed them defensively by a similar margin. Keeping possession of the ball helped teams score more goals and concede less by about 0.3 to 0.5 goals at both ends of the pitch. That’s almost a goal per match.
It seems natural to assume that more possession should lead to more wins and fewer losses. And it’s quite right: keeping hold of the ball, completing at a higher rate, and not surrendering it so often to the opposition means more wins, more points and more success. Teams that had the greater share of possession won 39.4 per cent of their games, compared to just 31.6 per cent if they had less. However, possession is measured – volume, completion, or overall – having more of the ball generated between 7.7 and 11.7 per cent more wins. It also decreased losses by around 7.6 per cent – about as much as it helped a team win. Turnovers are once again key here: teams lost 47.7 per cent of the matches in which they turned over the ball more than the other side; teams that gave it away less lost only 28.4 per cent of theirs. At both ends the possession game works and with spectacular results.
All this pays off come the end of the season. Clubs that had more possession dominated the top end of the league and those that didn’t were more likely to fight relegation. Clubs with more possession will win more and lose less. The average league position of clubs with more possession than the opposition was 6.7; the average for clubs with less was 13.8. Ultimately more possession and fewer turnovers added up to a more successful campaign.
In a nutshell, keeping the ball – and not giving it back to the opposition – is a legitimate strategy for winning football matches and not losing them. It improves the number of goals you score and limits the number you concede. Possession skill is often the key difference between successful and unsuccessful teams: conversion rates between those sides that succeed and those that do not, are about the same, but the successful teams produce a third more shots than the unsuccessful ones. It takes, on average nine shots to score a goal. You will score more goals the more shots you have, and you will produce more shots when you don’t give the ball away, either because you have the skill or because you have the strategy to play the possession game.