Mislabeled Data and Heat Maps: The Quiet Disease of Football Analytics

Three in the morning in Chengdu. On my desk sits a file with thirty-three data points, and in the top left corner the system has stamped a tidy label: football.

Inside are foreign direct investment falling roughly thirty-two percent in a fiscal year, a meeting between a chamber of foreign investors and a delegation from an international monetary fund, circular debt in the energy sector, reform of state-owned enterprises, questions of taxation and energy security. Not one team. Not one player. Not one minute of football.

I sat still for a while. The file was not hard to read. But I have met this situation too many times, differing only in the label. At sixty-nine, I have learned that the world still runs faster than I do, but longing always stands still.

The system asked me to fill nine analytical frames. Eight were empty. One was real. And they wanted all nine filled.

My trade does exactly this every week. We take a match, stick a few pre-printed labels on it, and write to fit the label. The label goes first, the truth follows, and usually the truth never arrives.

I came into this profession in 2026, starting at local radio stations, taking notes by hand and counting every touch. Fifty-three years watching the industry move. Back then I learned something that machines have since made me forget: a fact only means something when you know what it belongs to.

The label football stamped onto a macroeconomic news report sounds harmless. It is a miniature of something much larger. When a classification system gets the domain wrong, it does not merely corrupt a file. It forces a writer to fill empty boxes with guesswork. And in this trade, the reward usually goes to whoever fills the boxes most confidently, not to whoever dares to leave them empty.

In football, that empty box has a familiar name: the heat map.

The tool arrived as a convenience. Wherever a player runs, a coloured smear appears. Within a few seasons it became the most quoted object in analysis, and the most misunderstood. A major tournament with forty-eight teams will pour even more data onto our desks: more matches, more players, more coloured smears. The more labels there are, the easier it becomes to label wrongly.

I once sat beside a young colleague in a meeting room in Chengdu. He opened the heat map of a defensive midfielder, saw a small smudge sitting quietly in the middle of the pitch, and concluded that the player operates in a narrow zone.

A heat map answers the question where, while football is decided by the question why.

That small smudge is, very often, the best thing the player does for his team. The finest holding midfielders are usually the ones who move least. They stand where the opponent's backward pass is forced to travel, or where a teammate needs an escape route. They do not smear across the map, because their job is to stand still in the right place so that others may run.

Then comes the full-back. He has a smear stretching across nearly half the pitch, and the commentator praises his engine. But sometimes that smear is the trace of a mistake. He was dragged outside, the inside channel opened, a centre-back had to step out, and the whole defensive block spun like a top. Beautiful data can be the consequence of a poor decision, and if we stick the label of energy onto it, we have rewarded the error.

On the thirtieth of June, 2026, in Kazan, a nineteen-year-old Kylian Mbappé scored twice as France beat Argentina 4-3. I watched that match from the press room in Moscow and forgot to take notes. His heat map that night was a long diagonal streak down the right. Looking at that streak, one writes about speed, about legs, about youth.

But what made the match lay on the other side of the pitch. Argentina's back line started with an average age close to thirty, and they chose to push high. A high line met a pair of nineteen-year-old legs. The outcome was not on the heat map. It was in a decision taken before the ball rolled.

The data is not wrong. The label stuck onto the data is wrong.

On the eighteenth of December, 2026, in Lusail, a thirty-five-year-old Lionel Messi walked into the final that the whole world knew would be his last. His heat map that night was unremarkable: a small zone in the middle, slightly to the right. What made millions remember it forever was not inside that small zone. It was in the instant when an entire generation understood, at the same moment, that they were watching for the last time.

Mislabeling does not only happen at the level of players. It happens at the level of systems. A team with a low PPDA is called a pressing team, when what defines them is the trigger: whether they spring forward after a sideways pass back towards goal, or after a loose touch. Two teams with the same number can be playing two different sports.

At player level, there is expected goals. A striker who shoots ten times and does not score is called wasteful. But if all ten shots came from outside the box, through three bodies, the problem is not in his feet. It is in an attacking structure that creates no space. The metric measures the shot. It does not measure the person who made the shot possible.

I have also written about esports, where a small patch can change who wins the trophy without anyone calling it a coach. Teams that adapt quickly are praised for character. Teams that adapt slowly are dismissed as finished. Yet most of that gap is simply the distance between two versions of the game. Our eyes stick the label of quality onto something that is really timing. Football is the same, except that our invisible referee rarely shows himself.

In 2026, when the stands of Chengdu fell silent, a club that once drew forty-three thousand people per match was left with cicadas. I made video calls to fifty elderly supporters and recorded three hundred minutes of them telling stories about afternoons spent waiting for the ball to roll in front of old loudspeakers. Forty-three thousand, fifty, three hundred: those quantities never conveyed what I heard in those calls. Empty seats still ring with singing, because longing is also a kind of supporter.

Based on my experience of watching matches, I will say this plainly: the scoreboard has never been enough, and neither has the heat map. The only sufficient thing is patience.

Then comes the hardest part.

People usually blame the algorithm. I do not think so.

The maker of the wrong label is the demand to see every box filled.

The machine only does what we taught it: that a file must have a label, that a match must be split into nine frames, that a player must be given a rating. In sports journalism, the sentence not enough data to conclude is treated as weakness. The sentence he played a seven point five is treated as professionalism. But a rating with nothing to lean on is a polite form of invention, and it is more dangerous than a blank answer, because it has the shape of truth.

There is one principle I have kept for many years: praise the person, criticise the decision. It is easier to scold a player than to scold a system. If a striker goes three matches without receiving a single pass, the crowd will say he has lost form. Yet in most such spells the problem lies in how the team builds play, not in his feet. Blaming people is easy. Reading structure is hard.

The most dangerous case is when we label memory itself. A group of players is called a golden generation, and the name follows them to the end of their careers, through wins and through defeats. A young player is called someone's successor before he has played his first professional match. Such a label lifts a person for one evening and then presses on his shoulders for ten years. At sixty-nine, I have watched too many of these labels outlive the careers they described.

Back to the three in the morning file.

I left eight frames empty. I filled exactly one, in a single sentence: this content belongs to a different desk. No flourishes, no metaphors, no attempt to look knowledgeable. Then I sent it and went to sleep.

The next morning, the young editor replied in one line: Thank you. I almost made something up.

The pitch never betrays anyone; people simply forget that it also knows how to hold. I write slowly, because football is not in a hurry, it only waits for someone patient enough to understand. If there is one thing I want to leave the next person holding the pen, it is the right to say I do not know yet, and the courage to keep the box empty until there is something truly worth putting inside it.

When a young player walks into a meeting room with a heat map in his hand, will your first question be where he ran, or why he had to run there?