Vietnamese Volleyball and the Data Hunger: Lessons from an Analysis That Says 'Not Enough Information'

When the final whistle sounded at the most recent match of the Vietnamese Women's Volleyball National Championship, I opened the official match statistics sheet. All I received were basic numbers: total points, service errors, and rudimentary blocking stats. No spike efficiency, no perfect pass rate, no advanced metrics that could help me reconstruct the tactical flow. I remembered an analytical report sent to me via email – a document dozens of pages long, yet the recurrent phrase throughout was: 'insufficient information, cannot assess.' That is not an analysis; that is an indictment of how much data is still hidden in our volleyball. As a data journalist covering Southeast Asian volleyball, I frequently face such data scarcity. In football, xG and PPDA have become familiar to fans. Volleyball – a sport where every rally is a chain of measurable decisions – still lives in the dark age of box scores and basic errors. This not only hinders writers like me in proving our viewpoints but, more importantly, prevents coaches, scouts, and fans from possessing a map to locate their team’s performance. Consider a recent report sent to me. It mimics the structure of a professional volleyball analysis: technical and tactical analysis, data analysis, competition system analysis, competitive context, regulatory compliance, team management, risk assessment, and transmission mapping. Each criterion is listed. Yet under each metric sits a frustrating answer: 'insufficient information, cannot assess.' Eight domains, nearly forty assessment items, none with concrete figures. This is not the author’s fault. It is the fault of our current data infrastructure. Every piece of data tells a story; we just need patience to listen. But listening in vain when there is only silence is different. In modern volleyball, a team wanting to analyze opponent pressure requires a metric akin to PPDA – for instance, the number of passes the opposing team is allowed before being forced out of its defensive zone. Without such a metric, we can only say 'this team defends deeply,' a vague and meaningless comment. I was once invited to advise a Southeast Asian national team based on a pressing metrics report from football. If volleyball wants to advance, we must build a similar set of metrics. Doing so requires leagues to standardize data collection. Start with simple measures any match needs: first, perfect pass rate for each position. Without it, how do we know which team builds offense effectively from defense? Second, spike efficiency of outside hitters by zone. Is attacking from zone 4 more effective than zone 2? Without measurement, coaches can only rely on the naked eye. Third, the percentage of successful second-touch sets in transition situations. This directly reflects the setter’s ability to orchestrate. A team with high-quality second touches can run quick attacks, stretching the opponent’s block. In the data analysis section of that report, metrics like ace-to-error ratio and successful blocks per set were raised. We could not assess due to lack of standardized metrics. Most domestic matches are filmed with a single camera, without tracking systems. Even in the national championship, officials manually record statistics. Error is inevitable. Based on my experience following matches, I have seen official blocking stats undercount by as much as 30% compared to actual video evidence. When the numbers are wrong, any analysis built on them becomes meaningless. 'Numbers don’t lie, but they know how to hide the truth.' Hidden truths come in two forms: too few numbers, or numbers selected that don’t reflect the essence. For instance, focusing solely on total points per set might miss the fact that a team scores mostly off opponent errors – a gold mine that dries up over time. We need probability of scoring within a specific system, but if that system lacks serve data or combined attack data, we are guessing. The competition calendar also demands clear data. In the tempo assessment, we often hear 'tight schedule' as an excuse. But without data on travel distances, sets played per week, and the physical load on each athlete, the conclusion 'fatigue' is pure speculation. Beware of what you believe – data can erase it overnight. I have seen a team predicted to collapse due to fixture congestion still win because their opponents were even more tired. Measure actual sets with high-intensity movement volume, and we obtain an accurate answer. In the competitive context, many analyses merely list head-to-head records, forgetting that rosters have changed. A team may look strong on paper due to star signings but combines age groups inefficiently, making its actual competitiveness lower than its nominal rank. To identify this, we need data on playing time per lineup and performance in different situations. I have often faced teams with deep rosters but mediocre fitness in decisive stages. Without movement intensity tracking, fans are easily fooled by star acquisitions, while the role of quiet young players is undervalued. Another crucial aspect is regulatory compliance and squad management. 'Not enough info' reports usually omit this dimension because they lack data on contract validity, substitution counts relative to regulations, and violation penalties. The greatest risk Vietnamese volleyball faces is the lack of a standardized player database. A player changes a match. A statistic changes a campaign. In football’s transfer market, I have seen how data directs transfer decisions. In volleyball, clubs still sign contracts based on 'choose familiar people, avoid strangers.' Without a database to compare options, risk is enormous. But I must also stress that lacking data does not render all analysts powerless. Professionals still use qualitative observation and video analysis to offer insights. The wisdom of a head coach, the eye of a veteran scout, still count. However, from a contrarian angle, overconfidence in gut feeling is the enemy of progress. We can watch dozens of hours of video without realizing we are biased toward a few outstanding plays. Data – if accurately collected and complete – provides an unbiased mirror. It forces us to confront our own assumptions. I also admit that data can be misleading if processed incorrectly. In the 'insufficient information' report, the author seems to understand theoretical models well, but because inputs were missing, they wrote 'cannot assess.' This shows that good analysis requires not only a solid theoretical framework but also reliable data inputs. If Vietnam wants to move toward a professional volleyball industry, we must build data collection systems now. Each data table is a forest, and I am only tracking animal footprints. However, without the data columns, I cannot indicate that a spiker performs poorly against deep pushes. But if we collect data over one or two seasons, such patterns will emerge. Consider the rise of Opta and StatsBomb in football; they transformed everything from transfer decisions to coaching. Many clubs spend millions on data for just a 2–3% competitive edge. World volleyball has followed suit. Leagues like Italy’s Volley Serie A use Data Volley to track every rally; top national teams have video analysis departments using automated motion recognition. Meanwhile, most domestic matches still use printed scoresheets, and only a few international events have support from the federation. It is not easy to switch from an experience-based culture to a data-driven one. But I believe we don’t need a big-bang revolution. Each club could simply create its own statistics unit – even using Excel spreadsheets – to record crucial parameters in each match. A few seasons later, we would have enough data to uncover valuable correlations. Fans don’t need a destination; they need a map. That map should begin with a public, open data storage system. Media outlets also have a role. Instead of just reporting final scores, TV broadcasts should feature analysis shows that explain key indices. If fans hear explanations like 'spike efficiency of 45% means almost five kills per ten attacks,' they will gradually demand more. When I receive empty reports with 'insufficient information,' I am not discouraged. I see a positive signal: a report that honestly borders its limits. It does not embellish with luck-based judgments. But until federations and organizers require detailed data, analysts must work with half the information. I often joke that this job is like a detective with only half the clues. Yet sometimes I wonder: are we overcomplicating things? Experienced coaches, after many years, still build winning teams without complex data jargon. True, volleyball is a human sport: emotions, endurance, competition temperament can never be replaced by numbers. But numbers are not meant to be better than humans; they help humans make better decisions. Think of it as a mirror: adding nothing, reflecting precisely what occurs. Without a mirror, one uses water; a mirror is more accurate. That mirror, I dare say, will reveal lessons often overlooked by the naked eye. I am talking about a volleyball data project that some colleagues and I are nurturing. We aim to create an open platform where anyone can look up player performance in real time. The immediate challenge is the cost of hiring statisticians for each match. But with a coalition of stakeholders, we can make it work. This is how Vietnamese volleyball can avoid superficial chatter on forums. Finally, for readers still doubting the power of data: imagine your team’s last successful season. Can you recall precise statistics from those matches? You might remember the feeling of victory, but not why. Data answers the 'why' question objectively. Data does not create decisions; it kills doubts. Without data, doubts breed, and people believe unsupported opinion. To professionals, I hope this article serves as a reminder that we need unified data standards. In an analyst’s notebook, each match is a surgery; without data, surgery is impossible. I write not to prove I am right; I write to find out where I am wrong. And to know wrongness, we need data. Therefore, the 'insufficient information' report is not to blame. It startles me, reminds me, and prepares me for a long-term project. If Vietnamese volleyball – with increasingly high technical quality – truly wants to claim the Southeast Asian top spot, it is time to fill the data gap many countries have already crossed. I hope one day a professional volleyball analysis will have sufficient data to reach meaningful conclusions, no longer saying 'insufficient information.' Then the story of Vietnamese volleyball will be told in the most vivid language: the language of measured truth.