Manchester United – Conversion Kings

There’s a lot of discussion in the football numbers community about how perennially good Manchester United seem to be at converting chances. Why is this? Is it the type of chances they create? Is it simply that they have the best finishers? Or is it something else?

We decided to compare United with their closest league rivals over the last 3 years – Man City. Both have won the title in this period, and looked set to seriously battle it out again this year until United pulled away in spectacular fashion. We can SPAM both sides to compare the different shots both sides are taking and converting:


We can see that over the last two seasons, City have matched United’s number of shots from the “good” areas. However, United have been relentlessly good at converting these shots into goals in the central area of the box – the most important area of all. City have only come anywhere near United’s level here once – last year when they won the league. However, it was City’s extraordinary conversion rate from outside the box that appears to have nudged them towards the title. Immediately we can see why City’s form last year was going to be unsustainable.

Digging deeper, we can SPAM each of the team’s strikers to see their contributions to the team. The table below shows us first how many shots each striker has taken, then how many shots from each area it takes for them to score. It then tells us how many goals the average EPL player would score from the shots each striker has taken, and what each striker actually did score. Finally it shows how many goals above average they scored with each ranked for efficiency at the end:


Clearly United have the best finishers. The question as to why, however, remains.  Would Berbatov have been this efficient if he’d played for City instead? Why is it that Hernandez has scored 12 more goals than RVP from only a few more shots?

The SPAM figures above give us a good indication as to who avoids the decisions and pitfalls of your average striker – shooting from poor angles or from too far out, smashing shots into defenders’ legs or just plain missing the target. While it tells us the position of where the shot is struck, it can’t tell the positions of everyone else in relation to the striker when the shot is hit.

It’s fair to say that most teams playing against the top two don’t commit too many players to attack. The statistics tell us that United and City are among the teams who concede the least shots and spend the least time in their own half. Therefore we can assume that there’s a fair amount of defenders in the way when both teams try to attack.

At Differentgame we have a theory we wanted to test out. We reckon United commit more men to attack than any other team – even more than City did when they won the league last year. Unfortunately we don’t have access to all the footage from every game that year. So we did the best thing we could think of – we watched the goals both sides scored last season and noted how many attackers were in the box at the time.

We took out penalties for obvious reasons, then the other set-pieces as both sides were committing the same amounts of bodies forward. We also took out the long range efforts as often for both sides when they scored these, there was only one or sometimes no attacker in the box. This left us with open-play goals inside the box – the best indicator of how attacking the sides actually were.

The results? City had just under 3 players in the box on average when they scored and United had 3.8. Nearly a whole player more in the box on average. The number of bodies each had in the box got more interesting when we factored in game state:


We can see that when the game was tied United were slightly more cautious than City. When losing, United got busier than City. However, neither side was ever behind enough last season for this to make much difference overall. It’s when the teams were winning that the contrast became apparent.

When they got ahead last year City became more conservative. United on the other hand just got thirstier for goals when in the lead. Add in the assumption that opposition teams have to get more adventurous if they want to get back into the game and what you’re left with is the potential for carnage. United love filling their boots and they often do.

Van Persie scored more goals per game during his last two years at Arsenal than he’s scoring this season at United. However, the Dutchman is more clinical this year, taking less shots to score from that important central area inside the box. Next time you watch United, watch how much havoc they create when their attackers race each other to get in the danger zone. Defenders have a much harder time deciding whether to go and meet the man with the ball or block off space to the runner coming in. Often they end up doing neither. And if you give that extra bit of room to the strikers United are able to buy, you end up paying the price.

We think City got lucky last year. The knack they displayed for blazing goals from distance has waned as it was always going to. To boot, they’re back to being average inside the box for the chances they create. With the title finally won, did City become conservative this year?

United have gone behind more than usual this season. They’ve conceded before 15 mins is out 7 times. If the pattern from last year holds true, it means they’ll have been in the hunt very early on. And we saw last year that once they got one goal they won’t give up in trying to get another. They blew City away early this year, posting even more ridiculous conversion rates than previous years.

The success of supersubs like Hernandez and Solskjaer before him might be explained by this hunger for goals when behind or well in front.  The kind of out and out penalty box strikers that thrive on finding time and space amidst the chaos of a loaded box. It might also explain why United sought the services of Michael Owen despite his injury problems.

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