When the Data Sheet Is Empty: A Billiards Analyst Learns to Read Absence

Saturday night. A pool hall at the end of Lach Tray street, Hai Phong. Rain drizzles outside; inside, only two tables are still lit. I open my laptop and pull up the spreadsheet I built for the whole season. The player-name column is there. The match-count column is there. The points column, the break column, the number of turns behind the cushion, the time of each trip to the table – all empty. Not empty because I forgot to save. Empty because that night I wanted to analyze a match for which I did not have a single trustworthy number to begin with.

I stared at that empty sheet for nearly twenty minutes. An outsider would say: then go to sleep. But a data analyst understands that most of his job is not explaining the numbers he has, but facing the numbers he does not have. An empty sheet is not a failure. It is a result. And that result called "no data," if read correctly, can say more than ten pages full of figures.

Data never lies, but I have misheard it before. I first wrote that sentence at seventeen, after a night when my own spreadsheet betrayed me. Many years and many notebooks later, I still keep it as a reminder: the most dangerous thing for an analyst is not a wrong number, but a correct number read in silence, without context, without cross-checking, without a whole blank space in which to ask "what else is there?"

That night at Lach Tray I learned something no textbook teaches: a billiards analyst must have enough courage to write the word "unknown" instead of forcing out a conclusion. Because in billiards, unlike many sports, the accuracy of data is eroded by invisible things – the pressure of the tip, the humidity of the cloth, a slight tremor of the hand standing over the decisive cue ball. If you do not have the sheet to talk about those things, you should not say anything at all.

Let me tell the full story. That night I wanted to do something I do every week: analyze a billiards match. Specifically, a match in a tournament about which I knew every bit of context but for which I had not one officially reliable statistical line. No detailed frame-by-frame scorecard. No average time per trip. No safety-success rate. Just a video shot on a phone, off-angle, noisy, with scattered applause.

A greedy analyst would pounce on that video and "read out" all sorts of things. I used to be that greedy. And I used to be wrong. So that night I did the opposite: I drew up a list of conditions that had to be verified before I allowed myself to write any judgment. Who recorded the numbers? Recorded how – by eye or by software? Under what conditions – match table or practice table? Did the player know he was being measured? And most importantly: what is that number hiding?

The empty sheet that night was the answer to the last question. It hid everything, or in other words, it hid nothing because it had nothing to hide. I closed the laptop, took out my notebook, and wrote the first line: "Lach Tray night: insufficient data. The only conclusion that can be drawn is that this is unknown territory." It was a short sentence. But it was honest. And in this trade, honesty is the only asset that never loses value.

I bring this up not to complain. I bring it up because it relates to a bigger problem unfolding in professional billiards, and in how Vietnamese fans read billiards: we are obsessed with single numbers, with brilliant moments, and we forget that billiards is a sport of sequences, of rhythm, of repetition to the point of tedium.

One beautiful break says nothing. Three beautiful breaks in three consecutive turns start to say something. But thirty beautiful breaks in a season, set beside thirty beautiful breaks in another season, truly give us the right to ask a question. Here I want to talk about break data, century data, safety data – the things television viewers see on screen but rarely fully understand.

Let us start with the most abused number: the century count. In snooker, a century is a run of one hundred points or more in a single visit. It is the favorite measure of explosiveness, and also the most misread. People see a player make three centuries in a match and conclude at once: peak form. But the right question must be: against what opponent did those three centuries come, in what table conditions, at what stage of the match, and most importantly – did they come with a win?

I have a rule: never use a single metric to reach a conclusion. Whenever I read a statistics table, I begin with a list of "conditions to verify." For centuries: sample size in matches, opponent level, long or short format, and the rate of centuries per visit rather than the absolute number. Because a player who makes three centuries in fifteen matches is entirely different from one who makes three centuries in three matches. The same number, two opposite stories.

The same holds for pool and Chinese billiards. In 9-ball, people like to count successful breaks – break and runs. But a break and run only means something when set beside the player's own baseline across a whole season, and beside the baseline of the field. A player who breaks and runs twenty percent at a tournament might be a phenomenon; but if the field's baseline is thirty percent, he is below average. This is a mistake I once made, and I want to tell it as a warning.

Years ago, I was captivated by a young player with a string of beautiful breaks. I built a small model to prove he would dominate indoor events. The model ran smoothly. I wrote enthusiastically. Three months later, he lost repeatedly in the qualifiers. It turned out what I was measuring was not break ability, but the luck of a few perfect contacts under familiar table conditions. When he had to play on an unfamiliar match table, with different tip pressure and cloth, the streak dissolved like foam. I had misheard the data. Since then, every analysis of mine begins with two questions: where does this player play, and safe against whom?

A single mistake is an error. Three mistakes of the same kind are a signal. I borrow the spirit of my own line about goalkeepers and apply it to billiards: one missed break says nothing; three missed breaks of the same pattern – say, always leaving the cue ball in a bad position for the next turn – is a technical sign that needs dissection. That is when data becomes useful, because it helps us separate randomness from system.

But to do that, we need data. And this is where the empty sheet at Lach Tray comes back to haunt me. In Vietnamese billiards, data at a deep level almost does not exist. There is no system that automatically records every shot. There is no open data warehouse as in football, where anyone can download thousands of matches. To analyze billiards seriously, you must fill in the columns yourself. You must sit through video, time each visit, hand-record each safety. I once did this for twenty consecutive matches, and I understand why very few people do.

The problem with self-recorded data is subjectivity. When you watch and record at the same time, you bring your biases into every cell. You like a player, you unconsciously score his safety as "good." You dislike another, you score a similar shot as "lucky." That is why I always say a data analyst needs a second person to verify, or a set of criteria written before watching. Without pre-written criteria, every data sheet is a disguised memoir.

So when there is no data, what should an analyst do? My answer, after many years, is: narrow the scope of the question. Do not ask "who will win." Ask "can this player keep his safety rhythm in the first session." Do not ask "is his form good." Ask "what is his scoring rate in his first three visits." Small questions can be answered by quality observation. Big questions need big data, and big data does not yet exist.

I have applied this principle to my betting-analysis work. Here I must be transparent about limits: every conclusion in this piece is a personal view based on observation, not betting advice, and billiards is a sport of very high uncertainty. But methodologically, there is one principle I believe is right: better to skip a match than to publish a conclusion built on thin data.

There was a period when I had to relearn how to read a "blank" result. In statistics, the absence of evidence is not evidence of absence. It sounds philosophical, but it has formidable practical consequences. If I cannot find data showing a player has psychological trouble on decisive shots, that does not mean he is steady. It only means I have not yet measured it. This is the mistake I call "reading N/A as clean." In a spreadsheet, an empty cell is not zero. It is an unanswered question.

I do not write to persuade anyone. I write so that the data has a witness. I use this line when criticized for being too dry. But it is also why I record even my failures at data collection. An analyst is only trustworthy when he openly publishes the empty cells in his own sheet.

Now let us talk about professional billiards, where data is richer but still read emotionally. Snooker has a fairly complete statistics system: centuries, maximums, safety rate, average time per shot. These numbers are useful, but they also create an illusion of precision. For example, a player with a high safety rate might simply be a player who chooses a safety game more often, not necessarily a better defender. Safety rate depends on how many times you choose to play safe, not only on how many of those you win. Ignoring the denominator is a classic error.

I remember a match I analyzed for a small group of readers. Two players; one won with a superior safety rate. The majority concluded at once: the winner defends better. But when I re-timed every visit, it turned out the loser chose to play safety far less because he was forced to attack to catch up. He lost not because his defense was poor, but because he was forced into a game situation that did not allow him to defend. The winner's high safety number was largely a consequence of leading, not a cause. Correlation is not causation. This is what I want to stress most in this piece.

In billiards, the temptation to see causation is stronger than in many sports because each shot is a clear action attributable to one person. People want to believe the winner is better in every metric. But elite sport is rarely that simple. A successful break may come from dry cloth, new balls, or an opponent leaving a chance. A failed safety may come from a speck of dust on the cloth. Data records only outcomes, not conditions. A good analyst always asks about the condition behind the number.

This is also where I must speak about the human factor, which my quantitative foundation easily overlooks. Billiards is a sport where psychology shows more clearly than in most team sports. There is no teammate to shield you. No one to take the blame. Only you, the cue, and the distance between two balls. When a player stands over a decisive shot, his hand may shake. No data measures that tremor. No metric records the three-second pause before the stroke – a pause that can sometimes be longer than a minute on the clock.

I once watched a player lose himself on a simple shot. Before that he had made a long run, every metric beautiful. Then a basic shot failed, and from there he did not recover. Looking only at the final scorecard, one would conclude he lost on technique. But those who watched understood he lost because that moment severed his thread of confidence. The sheet was not wrong. It was just not enough. This is the boundary between analysis and storytelling, and an honest analyst must stand on both sides.

There is another topic I want to dissect because it is often ignored: the effect of spectators. In football, I once studied the no-audience summer and found home-field coefficients collapsing. In billiards, the effect is subtler. Billiards is a sport of silence. Billiards spectators do not cheer continuously; they hold their breath, then applaud at the right moment. That silence is part of the game. Without spectators, players lose that healthy pressure – and also lose the incentive of recognition after each good shot. Some play better with empty stands because they are less tense. Others play worse because they lose fire. No single number is right for everyone.

I tried to build a small metric to measure this, and I must admit: it was not convincing. Small sample, many confounding variables, and most importantly – there is not enough spectator data detailed enough for each billiards match. This is when I learned to say "my model is not good enough yet." When the stands are no longer a fortress, I learn to listen to empty stands. But in billiards, empty stands are not a variable as easy to measure as in football. It is a variable I am still trying to measure properly. And I make that public.

Transparency about limits is part of my method, but I know it can backfire if overused. If every piece ends with a long list of unknowns, readers leave. So I learned to gather limits into one short passage at the end, naming only those that truly affect the conclusion. The rest, I let the data speak. This is a lesson from years of writing: honesty does not need to be loud.

Back to Vietnamese billiards. I follow domestic players with special interest, because this is where data is thinnest but potential is largest. We have cueists capable of competing at regional and continental events. But we lack a record-keeping system. We lack a way to turn matches into numbers. A Vietnamese player plays well, but no one records that excellence in a way comparable over time. As a result, each generation starts from scratch, and technical lessons are not accumulated.

I believe what Vietnamese billiards needs is not a few more beautiful breaks, but a person holding a notebook. Someone sitting in a corner, quietly recording each visit, each safety, each pause. In ten years, that notebook will be worth more than every victory bulletin. Because victories already have people to cheer them. Data needs a witness.

There is a story I want to tell to illustrate the value of diligent recording. Not long ago, I spent three months recording every visit of a small tournament. Not a big event, no television, no scoreboard. Just me, the video, and the notebook. When I compiled it, I found a pattern no one noticed: in the third session of each match, players tended to play safe far more than in the first two. Not because they were tired, but because that is when they understood the opponent clearly and began calculating risk. The safety index rose steadily in most matches. It was a small finding, but it gave me a tool: when analyzing a match, I know to watch the third session.

That finding did not come from a complex model. It came from sitting and recording. And it reminded me that in an era when everyone wants an algorithm, the most valuable thing is sometimes just patience. Three thousand matches taught me that one match can teach more than all of them – but only if I sit down after that match and write down what I saw.

Of course, I do not delude myself that recording is enough. Self-recorded data helps, but it cannot replace systematic data at scale. That is why I always stress the importance of building data infrastructure for billiards. Professional tournaments need to start recording everything, publishing everything. When data becomes a shared asset, analysts, coaches, and fans all benefit. Without data, every debate about billiards is just a contest of prejudices.

I want to spend the final part on something I call "familiar prejudice." In billiards, there are beliefs passed down through generations: that young cueists are impulsive, that older cueists are slow, that East Asians have an edge in accuracy, that Europeans are strong tactically. These beliefs sound reasonable, but most have never been tested with data. They are repeated enough to become truth, though no one has measured them.

The analyst's task is to bring those prejudices into the light and ask: where is the evidence? When I began testing a few of these beliefs, I found they are usually partly right and partly wrong. The truth lies in the general trend; the error lies in applying it to individuals. The average never describes a specific person. That is why I never use a prejudice to predict a match.

This is the point I want to stress as a counterintuitive angle: in billiards, what we need is not more data, but more curiosity about where the data comes from. A beautiful sheet of unknown origin is more dangerous than an empty one. An empty sheet forces humility. A beautiful sheet gives the illusion of control. And the illusion of control is the enemy of every analyst.

That night at Lach Tray, I closed the laptop with an empty sheet. But I left the hall with one certainty: I knew that I did not know. That is a far better start than believing I knew everything. In this trade, one is easily tempted by the feeling of having grasped the rule. But the rule of billiards is not in the spreadsheet. It is at the intersection of number and silence. Those who see only the number will miss the silence. Those who hear only the silence will have nothing to compare.

The model knew in October. I was only brave enough to believe in May. I wrote this line thinking of the times data had already shown something I dared not believe, dared not publish. There are signals I saw early but stayed silent about, afraid of being laughed at. And there are times I published late, when the majority had already seen it. That delay is the price of fear, not of missing data. The Lach Tray night is a reminder: when data is absent, you must not invent it just to feel safe.

I want to end with an image. In the corner of the pool hall that night, an older man sat watching without playing. He looked at each shot for a long time, nodded, then wrote in a small notebook. Curious, I approached and asked what he was writing. He smiled: "I record the stances of the young ones. So that one day I can teach my grandchild." He had no spreadsheet. He had no software. But he had what many young analysts lack: patience and a notebook.

That image made me rethink my trade. We use algorithms, advanced metrics, pricing models. But the root of all analysis is still a person sitting, watching, and recording. When I call myself a "Data Monk" – a monk of data – I realize that monkhood is not accumulating a great deal, but knowing when to stop and admit emptiness.

The empty sheet from that night is still on my machine. I did not delete it. Every time I open it to analyze a new match, I keep it on a separate tab, as a reminder. It reminds me of three things: first, without data you should not conclude; second, the absence of evidence is not evidence of absence; third, an honest analyst is one who can write the word "unknown" without shame.

If you are a young player reading this, I hope you take away one thing: start recording yourself. You do not need expensive software. A notebook, a pen, and one rule: after each practice session, write down the three worst shots you felt and the three best. After a year, you will have something no coach can teach: a map of yourself. And that map will tell you what to fix long before the scoreboard says it.

If you are a fan reading this, I hope you take away something else: be suspicious of single numbers. When someone tells you player X is great because he has ten centuries, ask again: in how many matches, against whom, and did he win. Not to nitpick, but to understand more deeply. Billiards deserves to be understood more deeply than one brilliant moment.

And if you are an analyst like me, I hope you remember that our strongest tool is not the model, but humility. An empty sheet is not the enemy. It is the teacher. That teacher says nothing, but teaches the most: that the truth of a billiards match lies not in the numbers we have, but in the numbers we still lack – and in the courage to say so.

When the home arena is no longer a fortress, I learn to listen to empty stands. When the data sheet no longer has a single number, I learn to listen to its very silence. That is the lesson I carried from the pool hall on Lach Tray street, on a drizzly night, when I sat looking at an empty sheet and understood: in billiards, the most honest conclusion is sometimes just three words – not enough known. And I wrote those three words, not as a failure, but as a beginning. Because every serious analysis begins by admitting you know nothing, and ends by letting the data speak – even when that voice is a blank space.

Perhaps one day, Vietnamese billiards will have an open data warehouse, where a boy in Hai Phong can download thousands of matches and teach himself. That day, nights like Lach Tray will be less lonely. But until then, I will still sit here, with my notebook and pen, recording each visit like the old man in the corner of the hall. Not because I am sure I am right. But because I want, one day, when I look back, to have enough data to be wrong usefully.

And if someone asks why I remain patient with a sport whose data is as thin as billiards, I will answer with the line I still use whenever I am stuck: data never lies, but I have misheard it before. Precisely because I have misheard it, I know the value of listening again. Precisely because of those empty-sheet nights, I know the value of one correct number. Billiards taught me that patience is not waiting for data to arrive, but keeping a notebook ready so that when it arrives, we do not miss it.