Starting tomorrow, all of the D3 Volleyball World will be focused on the Sweet 16 beginning play. Even my last 4 posts are related to being preoccupied for this culminating tournament – First, forecasting who ‘d be in it, then reporting & commenting on who is in it, to those throughout history who have been in it, and yesterday providing team’s chances to advance through it, going so far as to have some fun telling a tall tale of competition between nicknames and/or mascots of the teams involved this year, too. Today, I’m going to step back to my curios roots regarding math & measurement related to volleyball tactics. I have exhausted my bandwidth writing about interesting curiosities regarding hitting efficiency, producing 4 posts related to the mindful traps (paradoxes) those who interpret them fall prey, now gravitating back to service. One reason for this because it is a contact measurable independently of any other, at least at its outset. Similar to free-throw pct. being more reliably measured than field-goal pct. in basketball – It is always the same 15 ft. to the hoop, with no proximity for defenders to alter a shooter’s readiness. i.e. Serving a volleyball from the same 30 ft. way from a net which is always the same height, and a target area never changing its dimensions. This while the player performing the skill sees where the opponent intends to initiate their offensive attack, should it gain possession of the ball. Just had a flashback to the one of the best sports movies ever made in history as I read back this last sentence! … I’m back … The receive positions itself for an attack before the ball is struck, one really good reason why serving a volleyball might be considered a defensive act. Unlike tennis, for example, where (s)he who serves a smaller, lighter weight ball, with a moment arm twice as long as his/her actual arm, producing speeds often more than twice a volleyball, gaining enough an advantage for it to be considered an offensive action. Where to begin dissecting a simple act of hitting a ball over a net with one’s hand if having an interest to determine how to best maximize chances to win a game? That is the rudimentary question to start.
A fundamental truth for winning volleyball games, whether side-out scoring from the past or rally scoring since the beginning of this century, is to serve more winning points than your opponent. Both teams side-out one to one, so there are two means to accomplish this objective. Either serve in a way to increase chances to win a point for the right to serve again, or pass an opponent’s serve in a way to increase the chance to prevent they from serving again. You’ve heard there are no second chances to make a first impression? Well, there are no second chances to touch a ball first, either. Why many correctly reduce the game to just serve and pass.
Like most studies, I need to start with mindfulness for a particular level of opponent, afterwards allowing to measure variability of these same constructs across any strength of opponent continuum. Typically, this benchmark is a skill level commensurate to that a 75th percentile of Men’s D3 volleyball teams in the country because the heart of my data is from observing teams better than the 50th percentile in D3. This makes the 30th best team a standard opponent to begin any analysis. (75 cents, the halfway point between 50 cents and $1, like the 30th best team being half-way between the best and the 60th best in the landscape. Also, a fundamental premise for determining TORA – the T100 SOS metric offered up every so often in this space.) It appears winning volleyball matches like these is prompted by a 38% point scoring rate. Point scoring is when a team serves the winning point for those not familiar with the common vernacular – I was someone not familiar with the game before the year 2000, so in the beginning I called them serve win rates and receive win rates because from my” “post 2000” perspective, they all are “points.” Therefore, a 38% point win rate (serving win rate) is the origin of everything to follow. My first thought is that when a server executes this skill there are 3 non-intersecting events which can occur as a consequence to their action. [1] A terminal point, [2] a point for which his team doesn’t gain possession of the ball, and [3] a point for which it does. The two subgroups of the latter would have to be gaining possession after an opponent passes in system (#3 in the diagram below) or gaining it after they had passed out of system (#4 in the diagram below). It leads to the following modified Venn diagram I believe lends itself to the demand for what a server seeks to make happen with their action:
So, how exactly will 38% point scoring get it done? When a team’s serve win rate and their receive win rate add to 100%, their opponent’s corresponding success rates do as well. This means they would be expected to win exactly half the time while serving an equal number of points as their opponent. However, a team which wins by 10, typically will serve 10 more points than their opponent (sometimes 9 depending on who served first in the set). This suggests their overall point win rate will be a weighted average, heavier to their serve win rate because it was performed more often than a receive. This is why the first table below is more than a simple average of its row and column margins. The overall win rate is the key component to predict the probability to win a set, and in turn, to then project a likelihood to win a match. As many already know, small gains in overall win rates create very significant gains in the likelihood of a success winning sets and matches. Look below to see how increasing a receive win rate 8% (from 62% to 70%), while maintaining a 38% point win rate, increases chances to win a set 17.2% (from 50% to 67.2%) and then makes it almost 30% more likely to win the match (50% to 79.8%) A powerful reason to want to curb errors because a team reducing errors by just 1 per set, not even assuming they would have won the point, if there had been no error, would produce greater than a 1% higher point win rate, which corresponds to an increase of roughly 8% more likely to win a set, for which a probability to win a match can raise as high as 15% or more. Of course the moments these point are scored or errored, and other variables related to win leverage will likely play their role, especially for less experienced players.
When measuring the ability for a volleyball player to finish a point (H%), the metric’s assumption is for the quality of passes or digs, and sets precipitating a swing remains consistent. The fact is, they just aren’t – Think in terms of sets Middles and Outsides generally get, and from what distance & the time required before contact to allow a defense to react. However, measuring a serve is more like measuring a foul-shot in basketball or a golf-shot. It has only the routine a player chooses to perform before executing it. (Except weather for golf, if you saw Friday’s round at the Master last week.) Every time, nearly exactly the same, because sports psychology has proven this leads to more frequent achievement of a goal. All of which makes measuring the ability for a volleyball player to initiate a point far more reliable than measuring his ability to terminate it, and I don’t mean something silly, like if a team scored a point or not when he served the ball. Both starting and finishing a point are certainly dependent on the skill level of any opponent, admittedly. Higher functioning teams usually block, dig, and pass better than those who aren’t. So any reliable service metric established for initiating a point (serving), just like H% measures its termination, must ultimately be determined as a function across the continuum of the quality of any opponent being played. That will lead to the 2nd post in a 3-part series early next week: Part Two- The SER Metric & Part Three – Should I Spin or Float?