smarterthinking

What does it mean to be good in the air?

It seems like such a simple concept, and one we hear about a lot: a player being "good in the air". But aerial skill can mean different things in different situations. We rate several specific kinds of aerial actions, but how can we see the whole picture?

The first and most importance distinction is between quantity and quality. Our style rating for aerials shows how often players engage in aerial duels, anywhere on the pitch, relative to other players at their position. That's quantity. For quality, things get a bit more complicated.

Todd Kingston, now at the New England Revolution in MLS, was the first person to propose a ranking method for measuring aerial skill. Since each aerial duel involves two players, we can rate them the same way we might rate tennis players or chess players involved in a series of one-on-one contests. For smarterscout, we don't use the same formula as Todd did – his was based on Arpad Elo's work – but the idea is similar: players' ratings change depending on how surprising is the outcome of each duel. If 1.93m Virgil van Dijk (rated 94) beats 1.63m Ryan Fraser (rated 12) in an aerial duel in open play, the result isn't surprising at all, and their ratings will barely change. But if Fraser beats Van Dijk, that's very surprising; Fraser's rating will rise a lot, and Van Dijk's will drop somewhat as well.

We rate duels in open play separately from duels from dead balls, because jumping to win a ball from a standing start may use distinct skills from doing so on the run. Some players are good in one situation but not the other; Jerome Boateng rates an 83 for aerials in open play and a 30 from dead balls, while Diego Llorente is rated 6 in open play and 84 from dead balls. We also handicap the duels using the players' locations on the pitch. This helps the ratings to converge to the "true" values more quickly.

For finishing skill in the air, we use the same sort of ranking method. We rate strikers and goalkeepers simultaneously across five categories of shots, handicapping the shots using expected goals. Two of the categories are for headers, again for open play and dead balls.

But for attacking aerials as a whole, these ratings still leave one question unanswered – who can win an aerial duel and then do something useful with the ball?

It's not hard to see who's good at winning duels. For example, with our "Search by metrics" feature, we can easily find the strikers active in Europe's top five leagues last season with 80+ ratings for both kinds of aerials:

Subscribers to our Data Scientist plan can add shooting to the query, too; they can search our entire database to find the players with high ratings for both aerial duels and finishing headers. Sometimes, however, the player's job is to flick the ball on, passing to a teammate. Again, the key is whether the player can control the outcome – can he win the duel and keep possession in a productive way?

To find out, we looked at all the aerial duels that occurred in since 2016-17 in Europe's top five leagues, but only in a small area of the pitch: a rectangle representing the last 10% of the pitch by length and the middle 10% by width. This area is right in front of the goal mouth, ahead of the penalty spot. And we didn't look at uncontested headers, because we wanted to focus on the most challenging situations.

Among players with at least 40 duels in a league (we didn't want to mix leagues, to ensure we maintained separate standards), these were the ones who had the highest share of productive actions after their duels:

In the Premier League, there was no one better at doing something useful with an aerial ball than the perennially underrated Craig Dawson. But if you wanted goals, then you had to go to Brazil for Richarlison or Roberto Firmino. Now let's take a glance at the Bundesliga:

Jhon Cordoba has been working away at smaller clubs for years, but he's got aerial skill for the biggest stages. Sandro Wagner and Naldo, the 1.98m giant CB who left Monaco early this year at the age of 37, are also very useful, but it's been a while since they scored. La Liga is next:

Gareth Bale might have been more beloved by Real Madrid supporters if he'd managed to score more of his chances in the air (or, you know, maybe not). Diego Godin created plenty of passes, but Willian Jose was able to both pass and score.

Now onto the mother lode. Just check out these Serie A aerial attackers:

For pure and utter danger in the air, no one can match Nikola Milenkovic. The 22-year-old Serbian isn't just a stone-cold aerial hitman, either. He's also a smarterscout young prospect who's put up excellent numbers at RCB by a Serie A standard for two years running:

Not bad for a guy who cost just €5m in 2017. Edin Dzeko is still a force to be reckoned with, too, as is Andrea Petagna, who may finally get his chance for Napoli this season.

Lastly, we move to Ligue 1:

Even the most successful aerial attackers in France don't seem that successful, and it could be because the defenders are at a relatively higher level – and that might make the Serie A attackers less impressive, too. This is exactly why we use league adjustments for our skill ratings.

It's also interesting to see that Ligue 1 players are more likely as a whole to look for a pass rather than shooting. There's a testament here to the late Emiliano Sala's skill in the air, and also another Brazilian CB still doing the business in his mid-30s: Dante.

Because these aerial opportunities close to goal are fairly rare, we shouldn't expect the charts above to be precisely predictive. In other words, we wouldn't put money on Andrea Belotti being that tiny bit better than Duvan Zapata in the coming seasons. Yet overall, the charts probably do a good job of identifying aerial threats, which Belotti and Zapata certainly are.

There are clearly differences in style, too. The light green bars that denote lost duels in the charts don't follow the same ranking as the bars denoting successful actions. So among these elite groups of players, the win rate in aerial duels close to goal doesn't necessarily correlate with the end product. To this point, Valere Germain loses plenty of duels but is deadly when he wins one. Hardly anyone wins a bigger share of duels than Benjamin Hubner, but he's not the highest scorer.

We think that aerial skill is actually a really complex trait to define. Clubs seeking a force in the air should think hard about the exact type of aerial skill they need, whether it's for an attacker or defender. Once the type of skill has been defined, we can construct the right metric to measure it.

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