The “Insufficient Information” Discipline: Nine Dimensions of Swimming Analysis and the Cost of Inventing Numbers

Hanoi, a morning in November. The analysis document on my desk has nine sections, all printed in the same neat type: technique; performance and data; competition system and entry mechanisms; the world swimming map; rules and anti-doping; athlete careers and team systems; risk profile; public opinion and expectations; industry ripple effects.

Nine sections. Not one of them contains a number. All nine carry the same sentence: “Insufficient information, cannot assess.”

I read it three times. The first time, I thought of a transmission error. The second time, I thought of a data-entry error. The third time, I understood: the analysis was not broken. It had just done the hardest thing in this profession — refusing to speak when there was nothing to speak about.

Sports writers in Vietnam are paid to have opinions. Nobody pays for blank space. But blank space is what keeps the rest of the piece from collapsing.

Why I am writing about nine empty sections

In August 2026, round 18 of the V-League, Hanoi FC hosted FLC Thanh Hoa at Hang Day Stadium. I was sixteen, sitting in front of a spreadsheet I had built myself, fourteen columns wide. Hanoi held 68 percent possession and fired 21 shots. Thanh Hoa took nine shots and won 2-1 through two Uche Iheruome counterattacks. It took me a week to understand that I had been deceived by the very numbers I had collected with my own hands.

The Hang Day shock taught me this: strong teams also know fear. Numbers forget to record that.

From that day I set a rule for myself. Never conclude on a single metric. Three sources, three different contexts, three different measurement methods. And if no source exists, the work to be done is to write that no source exists — not to fill the gap with a sentence that merely sounds plausible.

That nine-section blank document was the first test in years I was allowed to fail. It forced me to rebuild the entire analysis workflow for a swimmer, from the ground up, and to state plainly what data each section needs in order to come alive.

What data Vietnamese swimming has, and what it lacks

Based on my experience tracking domestic and international swim meets, Vietnam's swimming data system sits on two very different tiers.

The international tier is relatively complete. Results from meets governed by World Aquatics are published with detailed timing sheets: reaction time off the blocks, 50m splits, the 15m mark after the start, turn-in and turn-out times, and stroke rate by segment. If a Vietnamese swimmer competes at the SEA Games, the Asian Games or an Olympic qualifier, I can reconstruct almost the entire race from public data.

The domestic tier is thin. The national swimming championship, youth meets, the National Sports Festival — most publish final times and placings. 50m splits are not always posted. Reaction times are almost never available. For a meet where I want to analyse the turn mechanics of a fourteen-year-old from Can Tho, I typically have one single number to start from.

That is why I always write the “Method” section before the conclusion in every analysis. Readers must know how many eyes I am looking through.

The framework I use has nine dimensions, and I will walk through each one to show that an empty section is not laziness. It is a result.

Dimension one: technique — the thing eyes cannot measure

A swimmer who looks beautiful is not necessarily a swimmer who is fast. This is a sentence I have to say to my editors at least once every season.

To assess technique, I need five layers of data. First, the start and the underwater phase: reaction time on the blocks, speed off the blocks, number of dolphin kicks before surfacing, surfacing distance. Second, stroke structure: stroke rate within each 50m, distance per stroke, and the ratio between the two. Third, turns: approach time, rotation time, push-off time, and underwater distance after the push-off. Fourth, the finish: number of strokes in the final 15m and the drop-off compared with the previous 15m. Fifth, pool adaptability: 50m or 25m pool, outdoor or indoor, pool depth.

Without splits, I have nothing. A coach can tell me his athlete “finishes well”. I need to know how many percent slower she touched the wall compared with the previous 15m.

The simplest calculation in my trade is conversion efficiency. I take distance per stroke divided by stroke rate to get a theoretical speed. If theoretical speed is higher than the measured speed for that segment, energy has leaked somewhere — usually in body position, a crossed entry, or the ability to hold the body line.

If there are no numbers, I do not write this section. I write: “Insufficient split data to assess technique. Minimum requirement: 50m times and stroke rate.”

Dimension two: performance and positioning data

A time on its own says nothing. It only speaks when placed against three coordinates: the world record, the all-time list, and the current-season ranking.

I always check that number three times, across three different sources, and I name the source in the piece. If a result appears only on one site that cites no source, it does not enter my table.

There are two traps in this section that readers rarely notice.

The first is long course versus short course. Times in a 25m pool are always faster than in a 50m pool because there are more turns — and turns, for most swimmers, are the fastest part of the race. Placing two numbers from two different pool types side by side is a basic error. I still see it in a few transfer and sponsorship stories in Vietnam.

The second trap is the equipment era. Between 2026 and 2026, polyurethane swimsuits effectively rewrote the entire world record board. From 1 January 2026, the world swimming federation banned that suit generation, and an entire layer of records became historical data that cannot be compared directly with the present. Anyone who pits a 2026 record against a 2026 performance without a footnote is doing the job wrong.

A number must also come with its sample size. A single unusually fast swim may be a career peak, or it may be a timing-system error, a faulty starting block, or a pool with favourable currents. I need at least three comparable swims in the same training block before I conclude real progress has occurred.

Dimension three: competition system and entry mechanisms

Every swim meet has a different function, and reading results without knowing that function is misreading them.

The Olympic cycle is four years, the SEA Games two years, the Asian Games four years. One year may be a volume-loading year; another may be a peak year. A swimmer going 14 seconds slower than a personal best at a domestic meet may simply be mid-block — entirely normal. The same number at an Olympic qualifier is a problem.

Olympic entry works on two standards: the A cut and the B cut, published by the world federation for each event before every Games. An A cut is close to guaranteed entry; a B cut depends on remaining quota places and is decided on the final day of the qualifying period. A common misunderstanding among Vietnamese fans is to treat a SEA Games gold and an Olympic qualifying standard as adjacent rungs. They are not adjacent.

I have one rule for this section: if I cannot identify the meet, the athlete, the nation and the cycle year, I do not write about chances. I write that the chances cannot be calculated.

Dimension four: the world swimming map

International swimming has four clear tiers.

The dominant tier belongs to the United States and Australia. The US has depth across most middle- and long-distance freestyle events, plus a college system widely regarded as the world's biggest training factory. Australia has tradition in women's freestyle, backstroke and butterfly.

The first challenger tier includes China, Japan, France, Canada, Italy and Great Britain. China has made major strides in men's sprint freestyle; at Paris 2026, Pan Zhanle set the men's 100m freestyle world record at 46.40 seconds, according to figures published by the world swimming federation. France has Leon Marchand, who has taken command of the individual medley and butterfly. Canada has Summer McIntosh, a young force in medley and butterfly. Japan holds a respectable position in men's individual medley and the backstroke events.

The second tier comprises nations with a handful of top-16 athletes but not enough depth to hold relay places. Vietnam currently sits here, with a few athletes reaching Olympic qualifying standards in middle- and long-distance freestyle.

The potential tier is the rest of Southeast Asia, where national team depth amounts to a few people.

Drawing a map without names, events or nations is a meaningless exercise. I once received a request to “provide the map of Asian swimming power” and returned a single line: give me the event first.

Dimension five: rules and anti-doping

This is the section I am never allowed to skip, even when the piece does not touch on doping.

The international anti-doping system operates on strict liability. An athlete is responsible for any substance found in their sample, regardless of how it entered. That sounds harsh, and it is harsh, but it is the foundation that keeps the system functional.

There are three rule zones Vietnamese sports writers commonly mishandle. The first is therapeutic use exemptions: an athlete with an underlying condition may use a prohibited medication, but must have an approved exemption in place beforehand. The second is the whereabouts obligation and three missed tests within twelve months, which counts as one violation. The third covers technical rules inside the lane: underwater distance limits, the number of kicks permitted in breaststroke, and touch requirements.

In an analysis I separate three layers clearly: confirmed fact, unconfirmed allegation, and opinion. Blending those three is the fastest way to turn an article into a lawsuit.

Dimension six: athlete careers and team systems

This is the dimension I consider most important, and also the one most over-quantified.

A swimmer's career curve peaks at different ages by sex and by event. For men, most peaks fall between 22 and 27 depending on sprint or endurance events. For women, peak age arrives earlier, and here sits a variable every one of my models must defer to: the puberty barrier. A fifteen-year-old girl breaking a national record says nothing about her performances at twenty. Body composition changes, centre of gravity changes, feel for the water changes. Many promising young faces plateau or go sideways during that period, and not one of them weakened through lack of will.

Sport-specific injuries are also a mandatory variable. Swimmer's shoulder — supraspinatus impingement — is the most common injury in freestyle, butterfly and backstroke. Breaststroker's knee comes from the outward whip kick repeated thousands of times. Lower back pain is common in butterfly and in swimmers who turn frequently.

And I must state this as an explicit view: schedule density is the single biggest cause of injury. No medical team can save an athlete from a two-meets-a-week calendar sustained over months and compounded by intercontinental travel. The best prevention does not sit in the physio room. It sits with the person writing the calendar.

Dimension seven: the risk profile

I divide risk into six groups: competitive, career and system, doping, rules, psychological and public-opinion, and industry-level systemic risk.

Each risk gets a level, a probability, an impact and a mitigation. After the Christian Eriksen incident at Euro 2026, I removed the word “certain” from my professional vocabulary entirely. I replaced it with “low risk” and “high risk”, and I attach a risk-adjustment coefficient between 0.8 and 1.2 to every prediction. Below 1 means I am confident; above 1 means something is out there I cannot see.

A risk profile with no subject has no risk to assign. That is why section seven on the document in front of me was completely blank.

Dimension eight: public opinion and expectations

In Vietnam, the gap between expectation and data foundation in swimming is wider than in any other sport I have followed.

A SEA Games gold is a real achievement, worthy of respect, and I do not diminish it. But it says nothing about the distance to the world-leading pace in the same event. In middle- and long-distance freestyle, the gap between the SEA Games leaders and the world leaders is usually measured in tens of seconds over 1500m. A number no outlet wants to print, because it is not pleasant.

This is where I have to say something I know will offend: controlling the lane is a beautiful lie; the touchpad time is the glaring truth. In swimming there is no such thing as “controlling the tempo”. There is a lane, a wall, and a clock.

The heat cycle of public opinion is also worth tracking. A new national record typically generates a two-week media peak. Without a follow-up performance within three to six months, the temperature falls faster than it rose.

Dimension nine: industry ripple effects

Swimming radiates outward into a value chain of upstream, midstream and downstream.

Upstream is the youth training market, grassroots learn-to-swim centres, and the athlete supply pipeline. Midstream is the athletes and the competition system. Downstream is broadcasting, sponsorship, equipment, and derivative markets such as data and analytics.

In Vietnam, the upstream is swelling fast while the midstream stands almost still. The number of children learning to swim is rising; the number of swimmers competing at national level is not rising correspondingly. That is a classic phase misalignment.

I also track a phenomenon I consider a structural problem rather than a moral one: the commercialisation of women's swimming events. Many women's meets are set up as a line item in corporate social responsibility reports, with a budget sufficient to hold the event but not to run it continuously. A women's meet used as a communications prop will not produce a single downstream athlete.

And at the level of sponsorship contracts, I see a valuation bubble in the very young cohort. The naked gamble is this: signing a long-term deal with a fourteen-year-old before she has cleared the puberty barrier is betting on a variable nobody has measured.

The contrarian angle: the enemy is not the blank space

The nine-section blank document drew a predictable reaction: somebody suggested I “write a few provisional observations just to have a piece”. That was the moment I understood the biggest truth of this trade.

The danger to this industry is not missing data. The danger is the sheer volume of conclusions drawn from a single source.

Three sources, for me, is not a ritual. If three sources all point back to one original report, I have one source. If three sources come from three different contexts — an official results sheet, a direct interview, and an independent measurement dataset — then I have a frame.

I also have to discipline myself in the opposite direction. Every time I am about to write against the crowd, I force myself to ask one question: what if the crowd is right? If the answer is “the crowd is right”, I rewrite. Daring to defy consensus is a quality. Defying consensus mechanically is a tic.

My own preference for order carries its own risk. When the data does not match the result, my reflex is to re-check the data. But sometimes the data is right and my model is wrong. I have a fixed error-check procedure: before publishing, I write out three reasons my conclusion could be wrong, and I attach a section titled “Non-quantifiable variables” — listing injuries, psychology, disciplinary issues, and unexpected events my model cannot absorb.

I removed the crowd variable from my model and the model demanded an explanation from me. Since then, the “Non-quantifiable variables” section is mandatory, not an appendix.

Every lane sends a signal. The analyst does not decode it, but consents to listen. Most mistakes in this profession come from speaking before the listening is finished.

What remains after nine empty sections

I did not file the nine-section blank document with the newsroom. I filed it with myself.

What I gained was not a conclusion about a swimmer. What I gained was a map of what I still lack: 50m splits at national meets; reaction times at youth level; stroke rate and distance-per-stroke ratios; a public database good enough that anyone could check my work.

The duty of an analyst is not to be right. It is to say what the data wants said.

Three signals I will track over the next twelve months, published openly so readers retain the right to score me later.

The first is the publication of split data in the domestic competition system. If one national championship begins posting 50m splits for every event, the quality of domestic swimming journalism will change within two seasons.

The second is the performance trajectory of the young cohort born between 2026 and 2026 in middle-distance freestyle. If they sustain momentum past the growth phase, Vietnam can reach the relay-capable group at continental level. If they go sideways, the cause will almost always sit outside the pool.

The third is domestic schedule density. If the number of meets rises while rest days between them do not rise correspondingly, I will treat the coming season as a high injury-risk season regardless of results.

One question I leave open, and I think everyone in this industry should answer it before writing another piece: if the most honest answer to a question is “there is not enough information to answer it”, will readers pay us to say so. If they will, this industry will be different. If they will not, we will keep inventing numbers, and keep calling it by a prettier name.