Right or left?: Answering Celtic's Jota paradox

João Pedro Neves Filipe as his mum calls him, or Jota to Celtic supporters, has opened with a goal and three assists in two matches.

He has started the season as part of a mobile front three with Daizen Maeda on the left wing and Kyogo Furuhashi down the middle. Starting positions are no more than a suggestion as movement and overloading the opponent is the order of the day. Both wide players swap wings regularly.

The half-time withdrawal of the injured Maeda in Dingwall saw him replaced with Liel Abada on the right and Jota moving to the left. Two assists followed (one from a secondary action at a corner) as Celtic finally triumphed 3-1.

Some debate post-match focused on the question of whether Jota is more effective on the right or left wing... so that is today’s topic.

Positional history

Because players switch positions in-game it does make it difficult to be precise on the outcomes per position.

I do not go to that level with my own data as it would become so complicated to log every data point for every player for every position per game separately. I am not sure what the commercial data providers do but, generally, a player is listed as playing in one position per match so I suspect they have the same issue. So this carries a slight data health warning.

Across three sources, there is a similarity in terms of minutes spent on each wing:

Broadly he has spent 75 per cent of his career on the left wing and 25 per cent on the right. This is a trend repeated in his time at Celtic. Transfermarkt provides overall career stats by position.

Here is Jota’s goal and assist rates per position:

This seems quite conclusive in terms of goals and assists per 90 minutes. Jota has 0.13 more goals per 90 when playing on the left and 0.09 more assists per 90.

A return of 0.81 goals + assists per 90 is fantastic for a winger, by the way. As is 0.69.

However, actual goals and assists are not as insightful as expected goals and expected assists. Also, we can look at other metrics to assess, for his time at Celtic at least, whether is he more effective on one wing or the other.

Goal threat

Wingers are a primary source of goals in modern football. In the 1990s, wingers started to become inverted so that they could cut in on their stronger foot to shoot against the weaker sides of left-backs and left centre-backs. Goalscoring wide forwards such as Arjen Robben and Cristiano Ronaldo emerged.

Jota is a nice hybrid of traditional jinking provider and goalscorer. Here are some key goal threat metrics per position:

He has more shots at goal (3.37) playing on the left than on the right (2.9). His xG is 0.11 higher per 90. He also gets more touches in the box when coming in from the left.

This supports his actual goals data and the differential coming from the left or right is the same for both actual and expected goals.

The rule of inverting seems to hold true here. A right-footed winger cutting in from the 'opposite' side is more of a goal threat.

StatsBomb’s shot map for Jota in the SPFL in 2021-22 season highlights this well. Most of his shots are from the left side half-space or left side of the box.

Creativity

We have a range of creative metrics to assess Jota with, again bot from left and right:

The Portuguese attempts 8.29 crosses from the right compared to 7.29 from the left. He is far more accurate from the right with his passing as 3.01 passes are into the danger zone within the opposition box and central compared to 1.67 from the left.

He creates 3.53 chances per 90 from the right compared to 2.11 from the left. Consequently, his xA per 90 from the right is 0.63 almost double that from the left (0.34).

It seems that Jota is a more creative force from the right. This makes sense if you think of traditional wing play. He is able to get past defenders and then cross or pass with his stronger foot.

Additionally, his defensive action success rate is 30 per cent from the right and 25 per cent from the left.

I suspect this is due to being able to block the left-footed full-backs with his stronger right foot. When on the left he will generally be defending on his weaker side.

Conclusion

This experiment is another example where using advanced statistics is way more revealing than looking at the basic goal and assist data.

Using simple outcome data, you would conclude Jota is far stronger on the left-hand side.

An additional - non-data - perspective on the Celtic frontline is that a creative Jota on the right compliments the movement and goal threat of Maeda and Furuhashi in the other attacking positions. Maeda and Furuhashi are forwards while Jota profiles more like a winger.

When we use performance data specifically targeted at goal threat, creativity and defending a far more nuanced picture emerges.

Jota is more of a goal threat deployed from the left. This fits into the inverted winger model where wide forwards are encouraged inside to shoot with their stronger foot.

However, when deployed on his more natural “winger” side of right, Jota’s creative outputs are significantly stronger. Additionally, he adds more defensively off the right.

So, do you want 'Goal Jota' or 'Assist Jota'? Is Jota a more effective traditional winger than a modern wide forward?

Well, his overall expected scoring contributions per side are:

There we have it. Jota is expected to contribute 0.97 combined goals and assists on the right and 0.79 from the left.