When the Data Is Empty: A Lesson in Honesty for Vietnamese Football Analysis

When I received the second-stage analysis report for a football article, every data field was marked N/A. No tactics, no charts, no player names, no sources. For an analyst, there are two ways to read it: either it is a faulty product, or it is a reminder. I chose the second.

In more than thirteen years of observing football, I have sat in meetings where coaches trusted only their eyes, and I have also sat in front of enormous spreadsheets where no one knew what to ask. Vietnamese football is in a transitional phase. Many clubs in the V.League have begun using GPS, full-pitch camera systems, and match statistics. But the data remains scattered. Some clubs buy equipment without hiring readers; other clubs have analysts but not enough clean data. Between the two states lies a huge empty space.

That empty space reminds me of a line I often use when writing: there are numbers that do not appear on the stats sheet; they live between two touches of the ball. A touch is not just a dot on a map. It is the result of a run, a glance, a perfectly timed decision. A statistics sheet records the number of touches, but not why the player appeared in that exact spot. And that why is where tactics truly live.

In 2026, when football around the world stopped because of the pandemic, I volunteered to analyse performance for a young national women's team. They had only twelve matches that year. That is a very small sample by modern data standards. But in those twelve matches, I discovered their goalkeeper saved penalty kicks at a rate of 43 percent. That number did not appear in the official statistics. It was created by reading the shooter's hip movement. I did not find it in a data file; I heard it from the goalkeeper herself. She said: I do not need to dive quickly, I just need to watch the way the opponent plants their foot before shooting.

That was a huge lesson. Football never fits neatly into an Excel file. A laptop cannot measure confidence, cannot understand the noise in the dressing room, cannot feel the way an older player chooses the right moment to move. But data can bring us closer to those things, if we place it beside the human context.

Think about Cristiano Ronaldo at the 2026 World Cup. In the match between Spain and Portugal, I coded every action. The result showed Ronaldo reached a maximum speed of 9.8 km/h, below the team's average of 11.2 km/h. If you look only at that number, many would conclude he was slow, that he did not defend, that he just waited for the ball. But all five shots on target by Portugal in that game came from situations where Ronaldo chose his position near the box. He did not run a lot; he ran at the right moment. The speed data is not wrong, but it lies if not placed next to positional data and spatial maps.

That kind of data is absent from ordinary match reports. A match report talks about goals, assists, and cards. It does not talk about twenty metres of backwards movement before receiving the ball. It does not talk about the seventeenth pass in a combination sequence, the forgotten pass that stretched the defence. A season is not the sum of thirty-eight matches; it is the repetition of seventeen forgotten passes. I write this as someone who has spent five years watching data frames over and over again.

In that process, I learned something harder than any algorithm: knowing how to say I do not know. The empty report was a mirror reflecting the bad habit of modern analytics. We rush to fill empty spaces with speculative numbers. We prefer a beautiful chart to an honest answer. But a good analyst is not someone who always has a conclusion; it is someone who knows when to stop when evidence is insufficient.

Without input data, every tactical analysis is pure invention. Without player names, without match context, without source citations, every number becomes a guessing game. That does not mean we should hate data. On the contrary, we should respect data so much that we refuse to put stories into its mouth that it cannot tell.

Football in Southeast Asia in general, and in Vietnam in particular, is full of data potential. Youth national teams can use data to monitor training load. V.League clubs can use data to discover players who run a lot but without effectiveness. But the deeper need is to build an honest data culture. Instead of telling a coach that we have a perfectly accurate prediction model, we should say that data can help him ask better questions.

Beware of false certainty. The more numbers we use, the easier it is to fall into confirmation bias. If a metric supports our intuition, we highlight it. If another metric contradicts our view, we dismiss it as a measurement error. When Arnold Schwarzenegger talks about never quitting, he is not talking about speed. Ronaldo at 9.8 km/h is the same: it is not about slowness; it is about appearing at the right time. To see that, an analyst must be humble enough to listen to data instead of forcing data to repeat our prejudices.

In a corridor, if you only look toward the light, you miss what is standing in the darkness. Vietnamese football has a lot of light from goals and regional trophies. But if we look only at results, we might miss a quiet midfielder covering for the defense, a full-back who never scores but creates space, a goalkeeper who reads penalty kicks through foot movement. Data is not meant to replace emotion; it is meant to protect the stories few people see.

I do not know what the original author of that empty report intended. But it gave me a reason to write about the way we read football. When a report says N/A, it is a question mark, not an answer. It reminds us that missing data is not always a failure. Sometimes, it is a door to recognizing what we do not know. And it is precisely on that border between knowing and not knowing that tactics and art meet.

When the ball stops rolling, data still falls. But data falling does not mean we must pick it up and assign it meaning. There are times when the most honest action is to stand still, look at the empty space, and say that here, we still do not have enough light to see everything. The data corridor of Vietnamese football is beginning to be lit. But the lamp ought to illuminate the dark corners, not just the scoreboards already too familiar.