The Empty Box Score: The Limits of Data Analysis in Vietnamese Volleyball

At 22:40, in the small press room under stand B of the provincial arena. After a semifinal of the national volleyball championship, the organisers handed reporters a single A4 sheet of technical statistics. The spike-points column had numbers. The efficiency column was empty. The perfect first-pass rate was printed as 0%. I stayed an extra forty minutes with that sheet. Across four sets I had counted at least eleven balls delivered exactly into the setter's hands, good enough to run a quick attack. Not one of them appeared on the page. Wounds never lie, but they never tell the whole story either. A box score behaves the same way: it does not lie, it simply falls silent in a way that is much harder to notice. That A4 sheet is why I am writing this. Not to defend anyone and not to attack anyone, but to state plainly something my trade rarely admits: most volleyball statistics in Vietnam are being used incorrectly, and the error happens at the level of definition, long before it reaches the level of conclusion. Vietnamese volleyball has entered a phase where the volume of data is growing faster than the ability to read it. Over twelve years of covering the national championship in both the men's and women's branches, I have seen three technical tiers coexisting inside a single arena, and they do not share a single dictionary. The first tier consists of clubs with their own statisticians, two camera angles, and software that logs every rally beat by beat: first pass, set, spike, block, dig, serve, along with the landing position of each action. The second tier is clubs keeping pencil records on lined paper, counting only points and errors. The third tier is the organising committee, compiling a summary within twenty minutes of the final whistle so it can be handed to the press. Those three tiers speak three different languages. When a second-tier club beats a first-tier club, the box score cannot explain why. When a player moves from a first-tier club to a second-tier club, her entire past becomes a record that cannot be cross-referenced: one action, two definitions, two results. Youth tournaments sit entirely outside the system, so every assessment of an eighteen-year-old is almost always built on the memory of whoever was sitting in the stands. Off the court, the pressure to read numbers multiplies. Fans want to know which outside hitter attacks most effectively. Sponsors want to know whose name belongs on a jersey. Broadcasters want a one-line summary inside seven seconds of airtime. Live-data platforms want speed, and they pay for speed, not for definitions. In that current, the two concepts most often blended together are spike success rate and spike efficiency. Success rate divides direct spike points by total attempts. Efficiency subtracts spike errors and times blocked from points, then divides by total attempts. The gap between the two methods is not small. An outside hitter who attacks forty-five times, scores twenty points, commits eight errors and is blocked five times has a success rate of 44.4% but an efficiency of only 15.6%. Look at the first column and she is a star. Look at the second and she is a liability in the decisive rallies. What matters is that domestic box scores, in most cases, publish only the first column. Spike errors and times blocked sit scattered somewhere in a recorder's notebook, or simply do not exist. So when an article states that player X has a success rate above forty percent, the reader is being handed half the truth, and the missing half is the decisive half. Perfect first pass is even messier. FIVB grades the quality of a first contact on a scale where the top mark requires the ball to arrive precisely enough for the setter to run the entire tactical menu. Some domestic organisers record the top mark as merely reaching the setter's hands, regardless of whether the setter can still run a quick attack. The two scales can diverge by ten to fifteen percentage points on the same match, involving the same person. Take libero Nguyen Khanh Dang as an illustration of that mechanism, viewed functionally rather than as a judgement of her individually. A libero's job is to keep the reception system from collapsing, and her real value lies in keeping the team's second contact available. If the box score does not record first-pass percentage to the FIVB standard, the largest contribution of a libero becomes almost invisible in every comparative debate. People generally notice a libero only when she errs. By the same logic, match workload is the most badly treated category of data. Jump counts, landing counts, the number of high balls attacked, the number of continuous lateral movements inside the three-metre zone: these decide injuries, yet they appear on no box score handed to the press. Three seconds of judgement on court, three months of decoding in the medical room. When an outside hitter such as Tran Thi Thanh Thuy or an opposite such as Nguyen Thi Bich Tuyen carries hundreds of heavy balls per tournament, the trace of that load lives in the ankle, the Achilles tendon and the knee cartilage, not in the points column. A middle blocker such as Le Thanh Thuy carries a different kind of load: short but relentless jumps, single-leg landings after quick attacks, an entirely different injury mechanism, and equally invisible on the A4 sheet. On the men's side, names such as Ngo Van Kieu and Tu Thanh Thuan carry serve and spike volumes well above the average, yet no cumulative index for them has ever been published across seasons. People watch the highlight reel; I watch the injury reel. That habit began on an afternoon in 2026 in Hai Phong, when I was a trainee broadcaster and happened to sit beside the U23 team doctor during the interval. He showed me a player running with a hip-axis deviation of less than two degrees, and said that if the statistician did not record that detail, three weeks later nobody would understand why the player tore a ligament. The team doctor told me in 2026: do not ask a player where it hurts, ask him what he is hiding. At the modern level, the equivalent question is put to data: does this empty cell mean not measured, measured wrongly, or measured and withheld? Those three possibilities lead to three different decisions, and confusing them is the most serious analytical error I see repeated every season. If the empty cell belongs to the not-measured group, the correct conclusion is that the system's observational capacity has a problem, and the work required is investment or training. If it belongs to the measured-wrongly group, the correct conclusion is that the data-entry process is faulty, and the existing figures must be suspended rather than used for recruitment decisions. If it belongs to the measured-and-withheld group, the correct conclusion is that this is a relational problem between parties, not a technical one, and no software will solve it. The sheet I held that night, after cross-checking three sources, belonged to the second group. The software had the display configuration set wrong, and the first-pass column accepted no value at all. The problem was not the recorder's expertise but the absence of any cross-check before printing. A small technical fault, yet had I written my report from that sheet, I would have produced a false conclusion, and it would have outlived the truth. The biggest risk of the digital era is not a shortage of data. The risk is documents that are fully formatted, with titles, tables, columns and rows, but hollow inside. They manufacture a feeling of certainty with no foundation, and a feeling of certainty spreads faster than real data. I once watched a club prepare a contract based on the success rate of an outside hitter at a youth tournament, where every rally was recorded by hand and errors were folded into the attempt count. The result was a long contract for a player whose true efficiency was nearly half the figure on paper. After the first season, the club blamed the player. The origin of the problem lay in the sheet, not in her hands. Serving is the third category distorted by the same mechanism. The useful metric here is points won minus errors, because a powerful serve always carries risk. A team that wins eight points on serve and loses twelve in a match is deducting four points from itself, even though the summary sheet may show eight aces and look impressive. No volleyball club in Vietnam publishes this net figure across a season. Comparisons across competitions also require an adjustment almost nobody applies. An outside hitter who scores twenty points at a regional event against three weak opponents cannot be placed alongside one who scores fifteen at a continental event where every set has to pass a block twenty centimetres higher. A sample of three matches supports no conclusion at all. A sample of three matches against three opponents of different levels supports even less. And yet every season, exactly one week after a regional event, I read at least five articles asserting that a player has made a leap forward. Another branch of this story is the live-data market. Any statistics system fast enough for a coach to review footage during intervals is also fast enough to feed a bookmaker somewhere else in the world. Live data supplied to betting companies is the darkest side effect of the digitisation of sport: one source, two purposes, and the second purpose pays neither the players nor the league. When the odds move before spectators have seen the substitution, that is a sign a data pipeline is running faster than the human eye. There is no paradox here. The same technology both helps and harms, and anyone in this trade has to state clearly where they stand instead of praising digitisation in general terms as a good thing. What I object to in the current reading of data is not quantity. The demand for total transparency that many people are now shouting for can directly harm players. Workload data, injury logs and recovery indices are information opponents can exploit: knowing an opposite has a sore right shoulder lets a team push its entire defensive scheme to that side; knowing a middle blocker has not recovered her ankle lets a team change every quick-attack rhythm. Publishing everything is not the democratisation of information; it is arming the other side. What should be published is method, not raw data. Which definition was used, how many matches the sample covers, whether it was adjusted for opponent strength, and who pressed the final button before the figures were released. Those four questions are enough for an ordinary reader to judge whether a box score deserves trust. One more challenge must be raised, this time against the analytics community itself. When the data is insufficient, the correct conclusion is a suspended conclusion, and saying so is harder than it looks. In this profession, silence before a metric with too little support is treated as a lack of expertise, while speculation with a confident surface is treated as courage. I have written articles whose entire conclusion could only be that there is not enough data to conclude, and every time a colleague asked what readers were supposed to do with that. The answer, after many years, remains the same: knowing that you do not know is a conclusion of value. In volleyball, that kind of conclusion appears more often than people assume. A team winning three sets in a row with quick attacks does not prove it has solved the opponent's block; the opponent may simply be off rhythm. An outside hitter topping the group-stage scoring list does not prove she is the best attacker in the tournament; the box score may not deduct errors. A national team winning consecutive matches at a regional event does not prove that country's development system has changed; the draw may simply have been kind. Every strong claim needs a sufficient sample, a clear definition and an opponent adjustment. Those three conditions must appear together. Remove one, and the claim becomes a belief. So what Vietnamese volleyball needs, at both competition and club level, is a minimum data standard published before the season: the list of mandatory metrics, the definition of each metric, the unit of measurement, the cross-check procedure, and the name of the person ultimately responsible. Such a standard does not cost much money. It costs patience and discipline, two qualities Vietnamese volleyball has already proven it possesses, just not yet in the right place. If a competition publishes that standard next season, the first thing to happen will not be prettier numbers but a wave of arguments about how teams are actually playing. Those arguments are more useful than any summary printed in haste at 22:40. Are fans ready to read a box score that says not enough data in one of its cells, or do they only want to see numbers?