The Data Gap in Vietnamese Volleyball

My spreadsheet has fourteen columns. After four sets of a quarterfinal at an international volleyball tournament held in Nha Trang, thirteen of them were still blank.

The only column with data was the score — the thing the electronic board had already shown to the entire arena. Serve, first pass, set, attack, block, dig, error: not a single number recorded. The organisers published the set scores and the name of the top scorer. That was all.

I went home, reopened the match footage, paused frame by frame and typed it in by hand. Four sets, roughly 190 rallies, close to five hours. It was the only way to answer a very simple question: what did the winning team actually win with. I still cannot claim I have a complete answer.

That is the problem with Vietnamese volleyball, and it is not a technical problem.

A sport growing up without a measuring stick

Over the past decade, Vietnamese volleyball has shown almost every sign of a growing sport. The VTV Cup has been held annually since 2026, drawing national teams and strong regional clubs. The national championship, organised each year by the Vietnam Volleyball Federation, has sponsors, live television and paying spectators. The women's national team won gold at the 2026 SEA Games in Hanoi — the first time in more than two decades. Tran Thi Thanh Thuy went abroad to play in Japan and then Turkey. Nguyen Thi Bich Tuyen became the most talked-about name in the attack line.

Running parallel to those headlines is a gap almost nobody discusses: data infrastructure. In developed volleyball nations, every club or national team match is coded rally by rally using dedicated software. Each first pass is graded on a quality scale, each attack is tagged by tempo and type, each block records both the touch and the deflection. In Vietnam, the most commonly preserved artefact is still the scoreboard.

That gap is not a matter for a handful of analysts. It determines how a volleyball nation understands itself.

Four metrics that do not exist, and what their absence costs

The first is the perfect-pass rate — the share of first passes delivered to the ideal spot, allowing the setter to run the full tactical menu. It is the foundational metric of every modern system, because it determines what percentage of rallies a team plays in-system and what percentage it is forced to play out-of-system. Without it, we know a team scored 25 points, but not whether those points came from structured play or from pure individual effort.

A team can win 3-1 with a perfect-pass rate below 40 percent, and that is a warning sign, not an achievement. In my hand-logged records, I began tracking this in the 2026 season. My sample is small: 31 matches in the national league and international events held in Vietnam, all re-entered from video. The result cannot be treated as statistical proof, but it is enough to pose a hypothesis: in many of the matches I logged, the winning team had a lower perfect-pass rate than the losing team. They won on direct service points and on one individual's attack efficiency.

The second is attack efficiency by rotation. Volleyball has six rotations, and some are structurally weaker because the positions of the hitters at the net change. Nobody in Vietnam publishes points by rotation. So when a team loses two sets in a row in the same manner, we have no data to tell us whether the opponent read the play or whether our own rotation structure was exposed in advance.

The third is the block-deflection rate. A good block is not measured only by direct points, but by how many balls it deflects for the backcourt to dig and convert into counterattack. That requires a coder sitting in the right spot who understands the team's rhythm. A scoreboard never has it.

The fourth is dependence on a single attacker. I calculate it as one player's share of her team's total attack points. In some matches I tracked, it exceeded 45 percent. That is not automatically bad — every team has a primary hitter. But when it passes 45 percent and there is no second option, the team's chances rest almost entirely on the state of one human body.

People watch the kill; I watch the space before the kill. In volleyball, that space is the first pass.

Empty stands, empty data, and the habit of explaining with spirit

There was a natural experiment Vietnamese volleyball passed through that almost nobody exploited: the crowdless period after 2026. In football, I once calculated that the Bundesliga home-win rate fell from 43.2 percent in 2026/19 to 31.8 percent with no spectators. In volleyball the effect could be larger, because indoor noise directly affects serving and first passing — two actions that demand silence in the head.

I do not have a large enough dataset to assert anything. But I know one thing for certain: we missed the chance to measure it, because nobody was recording rally-level data at the time.

Instead, the usual explanation for a defeat remains unverifiable language: lost their spirit, lacked composure, could not hold the rhythm. I do not deny the psychological factor. But saying a team lost because it lost its spirit, while having no pass rate, no service-error statistics by set and no rotation data, is speculation dressed as a conclusion.

Data never lies; only people lie to themselves. And in Vietnamese volleyball, we are lying to ourselves rather comfortably.

The counter-intuitive angle: data does not create victories by itself

A caution here, including for my own work.

The first hypothesis for Vietnamese volleyball's progress is that technical capacity genuinely improved: better fitness, better individual skill, more players going abroad. The second is less discussed: part of the success comes from concentrating talent in a few outstanding individuals, combined with regional rivals going through generational transition and favourable draws. The two hypotheses are not mutually exclusive, and I do not have enough data to weight them. Anyone who asserts one confidently is exceeding their evidence.

There is something else: more data does not automatically mean better. An analytics department without the right reader produces a false sense of safety. I have seen datasets so complete that nobody used them, because coaches had no time to read them and did not trust numbers entered by someone else.

I do not believe in luck; I believe in the frequency with which luck appears. But frequency can only be measured when someone records for long enough.

What to watch in the next round

I do not expect a national league to publish rally-by-rally data soon. That needs software, trained people, and an organiser willing to accept costs that medals do not reward.

But a few signals are observable. First, the club that hires a full-time analyst — not a camera operator, but someone responsible for coding and interpretation. Second, the first competition to publish points-by-rotation after each match. Third, the number of Vietnamese players going abroad to compete, because that is a sign the outside market has read the data on them.

If those three signals do not change within two seasons, every step forward in Vietnamese volleyball will still depend on a few exceptionally strong and exceptionally skilled people appearing at the right moment. And when they are gone, we will be back in front of the footage, wondering what happened — while the answer sits in spreadsheet columns nobody bothered to fill.

An entire volleyball nation is growing up on feeling, and the only person who can correct it is the one willing to sit down after the arena lights have gone out.