Vietnamese Swimming and the Trap of Empty Analysis

It was 10:40 p.m. on a Wednesday in Thu Dau Mot. A message from an unknown number lit up my phone: "Hi, what were Huy Hoang's splits in the 1500m today? I saw online that his last 200m was incredibly fast."

I opened my three usual sources: the organiser's official results page, the electronic timing board from the venue, and the technical report signed by the referee. None of them had a final-200m split. The figure the reader had seen came from a repost in which the author wrote "it felt like" and then attached a specific, round, memorable number to it.

That moment told me more than any results sheet. The biggest problem in Vietnamese swimming right now sits in the data layer, and in the habit of filling gaps with imagination. In swimming, that gap is wider than in any other sport I have analysed.

Why swimming is the easiest sport to fabricate

I have worked in sports data for more than twenty years, nearly ten of them tied to the pool. Football has Opta, StatsBomb, hundreds of tracking cameras recording every stride. Swimming is different. A 1500m race has one sensor pad on the wall, one electronic scoreboard, and one backup stopwatch held by an official. If the organiser does not publish splits, the splits do not exist.

The paradox is that swimming is the sport Vietnamese audiences crave numbers for most. Every SEA Games, every time a Vietnamese athlete reaches an ASIAD or Olympic final, searches for results, records and gaps to rivals spike. The demand is real. The supply is thin.

And when supply is thinner than demand, the market manufactures substitutes. That is a rule, not an accusation.

Anatomy of an empty analysis

I once received an analysis document about a Vietnamese swimmer. I opened it. The title field read "N/A". The source read "N/A". The article type read "N/A". The list of information points — the most important part, the place every conclusion must attach to — was empty. The list of entities was empty too.

But the skeleton was full. A technical section, a performance section, a competition-system section, a world-landscape section, a rules and anti-doping section, an athlete-career section, a risk section, a public-narrative section, an industry-ripple section — all with headings, tables and input cells. Each cell was filled with one phrase: "Insufficient information, cannot assess."

Formally, the document was flawless. In substance, it was a mirror held up to my own profession.

What frightens me is not the empty cells. What frightens me is the human reflex in front of an empty cell: fill it. A less experienced analyst sees the blank "Technique — Freestyle" cell and immediately thinks of writing about stroke rate, distance per stroke, entry angle. It all sounds professional. None of it has any basis in the source data.

This is the point I want to make plainly: an empty analysis fails not because it lacks conclusions, but because it keeps the shape of an analysis. The shell makes readers believe there is meat inside.

In swimming, that shell is more dangerous, because the public has no tools to check. A football reader can open a stats site and verify xG. A swimming reader has nowhere to look. So they believe.

From Binh Duong pressing to the pool edge

In 2026, I analysed all 26 rounds of the V-League and found Becamex Binh Duong's PPDA averaged 8.4 — the lowest in the league. I wrote "Binh Duong pressing — a game that needs no possession" with 17 charts. It drew more than 250,000 reads. My reputation came from there.

There is a pressure nobody sees, but every team fears it. I named it: Binh Duong pressing.

But the biggest lesson I took from 2026 was not how to name a concept. It was that I had 26 rounds, 234 matches, thousands of possessions to attach to. I was allowed to conclude because I had a sample.

At the pool, I do not have 234 matches. I have a handful of appearances by a Vietnamese athlete in a continental final in a given year. That is a sample any properly trained person must hesitate before speaking over.

In 2026, when the Bundesliga returned with 312 matches behind closed doors, I had a giant laboratory and found home advantage falling from 54% to 47%, with home PPDA rising 0.9. When the stands are empty, every model collapses. I rebuilt from the half-burnt data.

That experience taught me something directly transferable to Vietnamese swimming: what determines analytical quality is not the sophistication of the model but the completeness of the raw data. With 312 matches, I dare to speak of trends. With three appearances, I dare only to speak of hypotheses.

Short course, long course: two worlds that must not be mixed

One technical error recurs in writing about Vietnamese swimming: mixing short-course (25m) and long-course (50m) results.

World Aquatics recognises two separate record systems, and the gap between them is not small. Short course has more turns, and each turn is a push-off that generates momentum. A swimmer with excellent turns can be markedly faster short course than in the same event long course. When an article places someone's short-course mark next to another's long-course record, it compares two different things.

I stress this because it is the hardest kind of error to spot. It fabricates no number. It merely puts a number where it does not belong.

Another example: women's 200m breaststroke and men's 200m breaststroke cannot be read on the same analytical frame, because pacing structures differ with height and arm span. Even between two athletes of the same sex and same event, a 1.70m swimmer and a 1.85m swimmer are solving different technical problems.

That is why I always state sample size and pool conditions at the top of an analysis. Not to show diligence, but so readers know the limits of what they are reading.

The interpolation trap

This is the part I want to give the most space, because it is the trap I nearly fell into myself.

Suppose I know a Vietnamese swimmer's total 1500m freestyle time at an international meet. I have no 400m, 800m or 1200m splits. In swimming, pacing structure decides almost the entire story: fast start and hold, slow start and a final-300m surge, or metronomic even pacing. These three tactics produce three entirely different athlete profiles and three entirely different training directions.

If all I have is the total, I know the outcome. I do not know how the swimmer got there.

An inexperienced writer interpolates. They pick the most plausible scenario — usually the one that elevates the Vietnamese athlete — and narrate it as something that happened. Readers cannot object, because the scenario does not contradict public data. It is merely one of several possibilities.

But interpolation is not analysis. Interpolation is storytelling with numbers attached.

I understand why people do it. When you must file regularly, when the newsroom needs content about an athlete in the spotlight, when your sources give you one fragment, the pressure to fill the page is real. I have been inside that pressure. I once wrote about a match for which I had only the scoreline and the scorers. I wrote about both teams' "tactical intentions". Then I watched the tape and found I had been wrong about almost all of it. From that day I set a rule: verify three sources before any number enters the piece, and state the statistical timestamp of every chart.

xG is not wrong; football is simply irrational. After 2026, I learned to count the irrationality too.

Applied to the pool: the irrationality here is the swimmer who exceeds themselves at the exact right moment, the breakthrough that training volume cannot explain. I do not deny it. I just do not force it into a model that cannot hold it.

Treating the gap as a variable

My method for missing data in Vietnamese swimming has three steps.

First, classify readable and unreadable zones. Total time, finishing position, personal bests, national records — these are readable, because major-meet organisers must publish them. Per-100m splits, stroke rate, turn count, average speed per lap — these are unreadable for most meets in the region. I state that boundary explicitly in the piece; I never let it blur.

Second, with a single observation I use the word "hypothesis" and say plainly this is one observation and cannot be generalised. Only with three or more observations showing the same signal do I move to the word "trend".

Third, I do not compare Vietnamese athletes with the world's best using absolute figures. I compare them with themselves at different points in time, and compare the gap to regional peers. That is the only way a developing swimming nation can read itself without being crushed by meaningless comparisons.

Numbers do not lie, but people always find ways to lie with numbers.

I wrote that a few years ago, and every season it becomes a little more true.

There is a subtler forgery than inventing numbers: choosing a real number and placing it in the wrong frame. Take the period when an athlete was at peak form, cut it off from the injury context, from the congested calendar, from the fact the swimmer raced multiple events in a single day. Then conclude about "true form".

In swimming, an athlete racing three events in one morning swims the third with accumulated lactic acid. Comparing that mark with a mark from a single evening event compares two different experiments.

People also forget age. For female swimmers, puberty can change height, arm span and body composition, shifting both technical parameters and results across one to two seasons. A dip during that window may say nothing about a career's future. Conversely, a jump in that window is not necessarily a product of coaching.

This is the zone where data is powerless, and I see no shame in saying so. I use numbers to map the boundaries of what numbers cannot explain. That, too, is a result.

Everyone wants a story; nobody wants a gap

There is a social force pushing this profession toward careless writing.

Fans want to believe Vietnamese athletes are improving faster than they really are. That is understandable and not wrong. But when a journalist correctly writes "there is not yet split data to assess this", the reaction is often disappointment. That piece gets fewer reads than one with a bold conclusion. The market's reward mechanism is rewarding false certainty.

I have been criticised for writing that Croatia at the 2026 World Cup were efficient because of their accelerations above 25 km/h per match. Many called it dry. I held the line with a long piece. After the tournament, that reading gained wider acceptance. But I paid by being seen as someone who does not write entertainingly.

At the pool, the price is higher, because Vietnamese swimming's audience is far smaller than football's. A cautious swimming piece might get a few thousand reads. A bold one might get ten times that.

I have no market solution for this. I have only one professional rule: if I cannot point to a source for a figure, that figure does not enter the piece.

Rebuilding something from the half-burnt data

While domestic swimming data remains thin, what I can build is not a results-prediction model. It is a map of the gaps.

That map looks like this. At athlete level, we have complete competition results but no training records. At competition level, we have schedules and entry lists but no publicly released detailed timing data. At international level, we have official results from continental and world federations, but no standardised cross-reference between pool systems.

Knowing those three gaps is far more useful than pretending we have a complete data system, because each gap points to a specific task.

A domestic meet that publishes 50m splits for every final would generate data we have not had for a decade. A federation that states pool conditions for every recognised record would end a wave of false comparisons. A standard naming convention for distances and events would make historical lookup possible.

None of that requires expensive technology. It requires a decision on standards, and one person accountable for enforcing them.

The counter-intuitive angle: silence is more useful than a conclusion

Here I want to go against my own instinct.

I became known for publishing predictions early. At Euro 2026, I called Italy as champions from the quarter-finals, based on a midfield that covered 4,200 km in the group stage with a PPDA of 7.6. At the Tokyo Olympics, I picked 8 of Brazil U23's 10 most important players correctly. Those calls worked because I had enough data to take a side.

But there is a kind of early prediction I have learned to refuse: early prediction about things that have never been recorded.

In Vietnamese swimming, a young athlete may appear with a notable mark at a domestic meet. I am asked whether they can reach continental standard within two years. The honest answer is that I do not know, and nobody does, because the deciding factors lie in things never measured — capacity for training load, recovery speed between sessions, technical stability under fatigue, and above all the coaching environment around them.

Offering a prediction here would make me look decisive. It would also make me part of a machine that manufactures expectations out of nothing.

I keep one boundary: it is permissible to predict when the signal lies inside the data; it is not permissible to predict when the signal is a reflection of my own wishes.

The biggest risk is not the article

I want to end with an observation about a deeper layer.

When an empty analysis is pushed out to the public, the short-term damage is that readers believe something untrue. The long-term damage lies elsewhere: it corrodes the standard.

Once audiences grow used to reading confident conclusions without sources, sourced pieces that carry boundaries will look feeble. The careful writer looks like someone afraid to conclude. Gradually, the careful writer chooses silence, or chooses to write like the crowd.

By then, Vietnamese swimming's thin data foundation grows thinner still, because nobody bothers to demand better.

Reputation is only a name. What remains is always the way you read the contest.

Signals for the next cycle

I am watching for three signs.

One: a national meet publishing detailed splits for final events.

Two: domestic record tables stating pool conditions for every recognised mark.

Three: a few swimming articles that dare to end with "insufficient data to conclude" instead of a tidy closing line.

The third sign sounds small. But if it appears, the others will follow. A sport only begins to accumulate data when someone is patient enough to read it, and brave enough to say they have not yet read anything at all.