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Three Principles for Solid Statistics


Sports statistics are changing the game and are growing in popularity because they ultimately help coaches and athletes monitor current performance while trying to predict future performances.

Volleyball is one of the best team sports in the world because of its rules. You must rely on your teammates by rule and cannot stall the game which makes collaboration the base of the entire game. Furthermore, at the high level it's as explosive as any other sport and very fast paced with a fast moving ball that must fall in 900 ft² area. If you add the fact that every point matters, it becomes logical why reading and understanding the game are such important factors at all levels of play given how fast decision-making has to happen in order to predict what is coming next.

Sports statistics are changing the game and are growing in popularity because they ultimately help coaches and athletes monitor current performance while trying to predict future performances. In volleyball, one-tenth of a second makes a huge difference and there is a somewhat preset sequence of events. Those two factors make it a great sport for data analysis and modeling.

Sports statistics is the collection and analysis of data with the ultimate goal of creating performance, health, and strength metrics to gain a competitive advantage for a team or individual.

Analysis of the data should facilitate any decision-making process, providing a "cold" analysis prior to or during a practice, a match, conditioning, scouting an opponent, etc.

With the data collection always being the tough part of the job, here are three principles that will guarantee quality data to study over and over without worrying that it might not be valid.

  1. Consistency is about making sure that the same data gathering procedure can be applied to all practices, matches, drills, etc. as well as consistency in comparing the same data sets.  Gathering data with consistency is important so that you can set accurate benchmarks.

  2. Accuracy can get better over time but using simple measurements will protect you from low accuracy. Do not go crazy with gathering all information, all touches, all everything; focus on key events.

  3. Precision is about being objective and creating a data gathering process that is as repeatable and as simple as possible in order to limit human error.

Whether you take stats on paper, a computer, or tablet keeping these principles in mind as you decide what data to gather, how to evaluate execution, and how to gather them. Also, use these principles to evaluate the quality of any data gathering service you might be using. At VolleyMetrics these principles are a big deal and they make a big difference.

On top of these three principles, there are a few tips for coaches to keep in mind:

  • Importance vs. Significance
    It is important to recognize that while something may be significant, it doesn't necessarily mean that it is valuable. If you have to increase your efficiency from .114 to .314 for a 5% game winning % increase, it's not the statistic you should focus on.

  • Focus on stats that you can control
    Just because a statistic is a great indicator of success doesn't mean that it should be focused on. An obvious and clear example is that even if opponent's service error % is very important, you can't affect how often it happens. Because of this, don't key in on this statistic. However, looking at your own error % can be helpful as it is still important and something your team has control over. (Basically, the old saying "think about your side of the net and the rest will come")

  • Focus on your individual team
    While the importance of overall skills are universal, the application of those skills can change. For example, efficiency is a great indicator of success, but if a team already has an above average efficiency rate, it may be more productive to focus on a less influential skill as it will be easier to improve, thus be more valuable to the team.

  • Avoid bad applications
    A simple and clear example of a bad application is "Serving more is highly correlated to winning. Therefore, I will simply tell my players to serve more." But to serve more, you need to gain the right to serve, which involves other fundamentals.

Lastly, I want to touch on this quickly and I will go much more in-depth in future blog posts but ultimately there are four common ways to gather data.

  1. Paper can definitely be the first step, although not necessarily the easiest. A coach can gather basic info or ask a player on the bench or even a parent to help. Truly, there aren't many good reasons that would justify not gathering even basic information, focusing on development and "your side of the net".

  2. Services that analyze the video for you and which in fact, are usually cheaper than gathering data yourself especially if you look at it from a time cost perspective.

  3. Mobile devices that allow you to quickly look up stats and so forth on your phone, iPad, or other tablets.

  4. Computer analysis, live or off video, allows gathering the most live data possible in the most efficient way. This last method usually requires much more training and practice but it's vital for teams who need to make crucial, informed, in-match decisions.

In conclusion, some of the main takeaway points are:

  • Gathering some data is much better than not gathering any data

  • Consistency, Accuracy, Precision

  • Statistics can point out what to work on

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