Nine Tiers of Swimming Analysis: The N/A and the Ethical Limits of the Number-Caller

From the stands of a 50-metre pool, I held a preliminary heat sheet that had just come off the photocopier in the corridor. Men's 200m individual medley. The eleventh line carried the name of a nineteen-year-old and a single number: 2:07.41. That was all. No 50m splits. No reaction time off the blocks. No average stroke rate. No count of underwater dolphin kicks after each turn. The sheet told me he was nearly two seconds off his personal standard, then went silent.

Where did those two seconds live? In the start, where a reaction time 0.15 seconds slow can cost half a body length? In the fifth turn, when the wrist is already tired and the foot meets the wall one beat late? Or in the final twenty metres, when lactate floods the forearms and every stroke becomes a negotiation with your own body? I had no answer. Not because I was lazy, but because the data needed to answer had never been recorded at the moment it existed.

In 2026, at nineteen, a second-year sports science student, I built a spreadsheet tracking 37 passes by Vietnam's U23 side in the attacking third at the 29th SEA Games. That sheet returned 0.68 xG for Vietnam in a 0-3 defeat to Thailand. The media talked about the scoreline; the spreadsheet said our midfield had been strangled in the centre of the pitch. That was the first time I understood that data can tell a different story from the scoreboard.

Football gave me a luxury swimming does not have: video. Every pass can be replayed, every press can be re-counted, every square metre of grass has a camera. Swimming is different. A swim happens once. Without an underwater camera, without automatic timing covering every lane, and without anyone storing 50m splits in a database, that moment vanishes from history the instant the hand touches the wall.

At many domestic meets, the only thing fully recorded is the touchpad time. For someone who works with numbers for a living, that is an audit where you are handed only the final invoice.

So I built nine tiers of analysis. The technical tier: start, turns, stroke rate, efficiency. The performance-coordinate tier: world record, all-time list, season ranking. The competition-system tier: heat structure, schedule density, selection mechanics. The world-map tier: the balance of power event by event. The rules and anti-doping governance tier. The career and team-system tier. The risk-profile tier. The public-narrative tier. The industry-ripple tier.

Every race is a confession; I am only the one who decodes the whispers from the scoreboard. I do not pray with bells, but with discrete strings of numbers every night.

That afternoon, all nine tiers came back with the same three letters: N/A.

The technical tier is where splits decide everything. Reaction time off the blocks for a senior swimmer typically falls between 0.60 and 0.75 seconds; the gap between the fastest and slowest reaction in the same final can reach 0.2 seconds, nearly a quarter of a body length by the fifteenth metre. The rules permit swimming underwater for a maximum of fifteen metres after the start and after each turn; a swimmer who surfaces two metres early loses speed that nobody records. Stroke rate and distance per stroke pull in opposite directions, and the SWOLF score merges both into a single figure. For a 200m event, this tier needs at least four 50m splits, one reaction time and one turn report. I had exactly one touchpad number.

The performance-coordinate tier demands three reference points: the world record, the all-time list and the current-season ranking. All three are meaningless without a declared equipment era. The 2026 to 2026 window saw more than forty world records fall in swimming at the Beijing 2026 Olympics, largely thanks to polyurethane suits; from 1 January 2026, FINA banned non-textile suits from elite competition. A careless writer places today's result beside a 2026 record and concludes this generation is weaker. A professional writer declares that the old record belongs to the suit era, and that any cross-era comparison needs an adjustment factor or an honest refusal. Over 200m, a 25m pool contains seven turns and a 50m pool contains three. Short-course results do not convert directly to long course, and anyone adding or subtracting the two is doing arithmetic on two different units.

The competition-system tier is about density. A typical national meet squeezes heats, semi-finals and finals into a single day, sometimes less than forty minutes apart. A twenty-year-old swimming two individual events and two relays across three days is routine, but this tier warns that a final time may be discounted by the schedule itself rather than by ability. Officiating risk also lives here: one false start erases a result from the record, dragging a whole chain of later comparisons with it.

The world-map tier divides power event by event, not by medal table. The United States holds the upper hand in women's middle and distance freestyle through Katie Ledecky; Australia has risen in women's freestyle through Ariarne Titmus and Mollie O'Callaghan; Britain once set the standard in men's breaststroke through Adam Peaty; Sweden sustains its position in women's butterfly through Sarah Sjöström; France found its centre of gravity in Léon Marchand at Paris 2026. For Vietnam, Nguyễn Thị Ánh Viên and Nguyễn Huy Hoàng are the clearest reference points; but this tier does not ask how many stars we have, it asks how many layers the talent supply chain holds. A swimming nation with only two internationally competitive names still appears as a single dot on its own internal map.

The rules and anti-doping tier forces the writer to separate fact from suspicion. The A-sample and B-sample process, the right to request backup-sample analysis, and the principle of not naming an individual before an official ruling are boundaries you do not cross for a better headline. One test question suffices: if the person in the story were my relative, would I write exactly this?

The career and team-system tier sends me back to my own eight years in the water. A swimmer's performance curve is not a straight line upward; female swimmers entering puberty between thirteen and sixteen can lose an entire season's physical advantage, and that is biological data, not data about willpower. Around it sit coaches, training plans, recovery facilities, the number of double-session days and the actual rest days in a year. Without those figures, any judgment about a step forward or backward is guesswork.

The risk-profile tier ranks by probability and impact. Shoulder and lower-back injuries in freestyle and butterfly; over-competition at junior level; the risk of being dropped from a national team because of one faulty timing pad; reputational risk after a defeat. I always put the probability column before the impact column, because most risk in youth sport is low-frequency risk that can end a career.

The public-narrative tier is the easiest to be fooled by, because it runs on the press-conference question: will there be a record. An empty stadium is the strange marriage of data and loneliness. In 2026, re-watching all 98 Bundesliga matches of the 2026-20 season from tape, I found the home win rate fall from roughly 45 percent to 23 percent with no crowd present. An empty pool shifts the rhythm in a comparable way, which shows that crowd expectation is a measurable variable, not a literary mood.

The industry-ripple tier reaches beyond the lane rope: the suit and goggle market, meet organisers, timing systems, pool investment, and a data market that barely exists in Vietnam.

An analysis is only credible when it dares to declare its own blank spaces. Those nine tiers are not a ladder to climb toward a conclusion; they are nine doors that are allowed to close. When the technical tier has no splits, the correct answer is insufficient data. When the performance tier has no declared equipment era, the correct answer is insufficient data. Saying so does not make me weaker; it only gives more weight to everything I say afterwards.

The real problem for Vietnamese swimming is not the nine analytical tiers but tier zero: the data-collection tier. We are decorating floors eight and nine while the foundation is missing. 50m splits, reaction times, turn reports, distance per stroke, breath count per lap: those are the cheapest bricks and the ones fewest people want to lay. Numbers speak out loud, but nobody asks how many times they have wept.

The irony is that my profession rewards the opposite. Sports analysis pays for certainty. The writer who says this athlete will break the record gets shared everywhere; the writer who says I have no splits so I will not conclude gets called passionless. Same newspaper, same dataset: the loud one always beats the correct one.

I know that trap because I have fallen into it. At Euro 2026, then an assistant analyst for a betting firm in Hanoi, I noticed Italy posted a PPDA of 8.5, the best in the tournament, while the other major sides were all above 11. I persuaded my boss to back Italy to win at odds of 11/1, they lifted the trophy, and the company booked a record season. But in the reasoning behind that decision, confidence outweighed the evidence I actually held. Had Italy lost in the semi-final, I could not have told you where I went wrong, because I had fused two different things into one sentence: high probability and certainty.

Since then I have set myself a rule: whenever new data overturns an old conclusion, I publish a correction and name that series outright, When I Was Wrong, the Numbers Were Right. In a betting market, the person who survives longest is not the best predictor but the one who stakes least on what he does not yet understand.

The paradox is that the data gap itself is the largest remaining competitive advantage for Vietnamese swimming. In a market where everyone holds the same dataset, the edge is zero. In a market where almost nobody stores splits, the first person to build a standardised collection system for domestic meets will own the next ten years of analysis in this country. The work is unglamorous: one underwater camera per lane, one sheet of 50m splits, one open database, and one naming convention covering both 25m and 50m events.

Has the loneliness of that nineteen-year-old been recorded by any number at all? As of today, not by a single one. And that is the only piece of data in this article I am certain about.