When Data Is Labeled Football: Lessons from Vietnamese Football Pitches

I sat in the last row of Hang Day Stadium on an afternoon without a match. The stadium management was checking the floodlights; a cleaner wiped the substitutes' bench and picked up empty bottles. I turned to a colleague and said, "I learn more from the one sitting at the end of the bench than from the one lifting the trophy." He laughed, thinking I was joking.

Last week, I received a file from an automated news aggregation system. The file was labeled "Football", but inside there was no match, no player, no coach. It was about a Mexican airline, an anti-corruption agency, and more than fifteen million records allegedly offered on Telegram. I read it three times, looking for club names, league names, player names. There was nothing. A system had mislabeled a cybersecurity story as football. At first I wanted to ignore it as a technical error. But the more I thought about it, the more I realized it was not a joke.

In Vietnamese football, data is becoming a new language. V.League press conferences now feature more rankings, heat maps, and expected-goal charts. Clubs hire analysts, bring tablets to the pitch, and film every training session. Fans are taught to read numbers: possession, pass count, dangerous attacks. Yet, like that mislabeled file, a lot of our sports data is being read incorrectly. I have followed domestic football for twenty-two years, and I have never seen a period when people talked so much about tactics but understood so little about human beings.

Data is like a map. A map can show the route from Hanoi to Thanh Hoa Stadium, but it cannot show the smell of grass, the glare of floodlights, or the breathing of a player after a hard first half. A map drawn with the wrong scale will lead you to a dyke instead of a pitch. A mislabeled data table is exactly like that map. It looks clear, it looks scientific, but every row of numbers may be a cropped perspective.

The market loves labels. A player who scores in two consecutive games is quickly called a goal king. A goalkeeper who concedes from a penalty is immediately called a traitor. Those labels stick even when new evidence appears. One season, I saw a young defender criticized by the crowd after a defeat. Three months later, he cleared a shot off the line in a relegation-deciding match. But the label "mentally weak" was still there, like an old article that nobody had taken down.

The clearest example I remember was a contract from last summer's transfer window. A young winger was sold cheap because his heat map was not impressive. The data showed few runs down the flank, few successful crosses. The coach was forced to let him go because the board wanted to cut wages. Six months later, he scored three goals in four matches in the second division, then was called up to the national team for a friendly. I met his former agent, who said, "If they had watched the match where he did not score, they would have seen him pulling the defensive line apart for the striker. But nobody watches matches with their eyes anymore; they only read spreadsheets." That story reminded me of a line I often write in my notebook: "A forgotten contract can change the wind of a season." The young player was not in the expensive transfer list. He was a name crossed out, and that crossed-out name changed a team's promotion dream.

Based on my experience following matches from the V.League to the national team, I see a rule: numbers usually tell the story of those who have already succeeded, not those still on the journey. A defender may pass wrong ten times but once open up the decisive goal; a striker may hit the target five times without scoring. If you sit long enough in the stands, you will see details that statistics never store. Football is not just about having the ball; football is about choosing the right moment, and moments have no dedicated data column.

I remember an evening in Thanh Hoa. After the match ended, reporters surrounded the goalscorer while the reserve goalkeeper quietly walked toward the dressing room with the ball. Nobody interviewed him. But he had spent ninety minutes watching how the opponents shot, and the next morning I saw him advising his teammates about long balls. People look at the scoreboard; I look at how players breathe when the ball goes wide. That is a different kind of data, one that cannot be squeezed into a spreadsheet.

In 2026, when the pandemic left stadiums empty, I asked to enter Seoul World Cup Stadium twice a week. Kim Sang-oh, a groundsman who had been tending the pitch for fifteen years, still cut the grass even though there were no matches. My series "Silent Pitch" later won a sports journalism award. That was when I understood that noise is not football. Football is what remains when no one is watching. A reserve player still trains hard even when his name is not on the roster. Some values cannot be observed through data models, because they live in the eyes of fans and in the patience of the forgotten.

I also witnessed a data error inside a V.League club. A newly graduated analyst was asked to compile foreign player profiles. She used old software, player names were mixed up, and appearances were doubled because two competitions overlapped. The report recommended a Brazilian centre-back with good statistics, but he had actually been out for six months with injury. Fortunately, the sporting director knew the transfer market well and called a friend in Brazil to verify before stopping the deal. Without that call, a hundred thousand dollars could have been poured into the wrong name.

I have a habit of checking three sources before publishing a piece. Colleagues call me a gatekeeper. But I believe that in the age of data, checking the origin of a number is more important than checking the origin of a rumor. A wrong number printed three times becomes six times the misunderstanding. A young player undervalued by an algorithm has no right to explain himself. Algorithms do not apologise.

Contracts are another kind of label. People look at contract length, release clauses, salary figures, and attach a value to a player. The transfer market is where people pay for the future but often forget the past. A player sold cheaply because of injury may become the pillar of a new team; a player bought at a high price may never adapt to his environment. Value does not live in a contract; it lives in how a player is treated every day.

The bigger question is who takes responsibility when wrong data spreads. If a cybersecurity article is labeled football, readers can move on. But if a player is labeled "past his prime" by an algorithmic model, he may lose his career chances. The label is not printed on his shirt, but it can be printed on the decisions of sporting directors, broadcasters, and fans. I have seen many Vietnamese clubs change coaches because of a short losing streak without asking what the team was building behind the bad numbers.

Fans may remember how many goals Nguyen Quang Hai scored at the SEA Games, how Do Hung Dung opened the score in the AFF Cup final, or how Nguyen Tien Linh headed in the decisive goal. I remember those things too, but I try to remember another layer: how they treated their substitute teammates, how they stood when the ball went wide. At one national team training session, I saw Pham Tuan Hai stay behind to take ten extra shots after the cameras had left. No news story covered it, but it said more than any chart.

The irony is that fans believe data will remove emotion and prejudice. A ranking looks more objective than a hasty comment. But data is created by people. It begins with a question, a definition, a comparison. If the question is wrong, the wrong answer becomes even more convincing. Every number stands on an assumption, and if the assumption is wrong, the number is just a shining label. If a player is put on a "redundant" list because his heat map is not green, that is a wrong label. If a coach is labeled "negative" because his team has low possession, that is also a wrong label. Football cannot be reduced to occupying more of the ball.

In the V.League, I have seen many teams defend and counter-attack while still beating teams that kept possession. Possession data may say they lost controll; the eye shows they won through intention. Coach Park Hang-seo taught the Vietnamese national team to defend actively, and many people doubted him. But the results on the pitch were trophies, while the numbers remained just numbers. Vietnamese football needs data, but it needs even more people patient enough to sit down, watch a whole match, and record the variables that do not appear in software.

During big tournaments like the AFF Cup, the pressure of labeling becomes harsher. Fans eagerly wait for the national team to show its identity. One draw produces hundreds of articles concluding the team is declining. One narrow victory makes many forget that the opponent played better. I do not want to write the same kind of conclusion. I want to look at how the team breathes when the ball goes wide, how they stand when they are pressed, how they pass to each other after a wasted chance.

The biggest lesson left by that mislabeled file is not about technology. It is a reminder that every label has a creator, and every answer can be wrong if the initial question is not honest. In football, that means: before trusting a report, ask where its author stood, what he saw, and what he missed. The best sports writer is not the one who runs fastest, but the one who stays longest. This season, I will arrive at the stadium a little earlier. I want to see the people behind the substitutes' bench, the players whose names never appear on the scoreboard, the groundsmen working in silence. Because one day, one of them will change the course of a season — not through a report, but through an act that no one records.