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Types of Performance Indicators Used in Volleyball | Their Definition, Calculation, Example, Pros and Cons
Types of Performance Indicators Used in Volleyball
There are several types of performance indicators used in volleyball. Performance indicators are important because they create a level playing field so we can understand and compare different levels of performance (click on this link to read more). I will outline their calculation, definitions, examples, and pros and cons for each type of performance indicator. These can be applied to an individual or team and for any technical skill, assuming the required stats are recorded. The only exception is the Sideout and Break Point %.
I will describe “perfect” actions as any actions that lead to a point won (kills, aces, block kills) and any actions that led to a perfect first ball contact (pass or defence). “Errors” are any actions that led to a point lost. Total Attempts refers to the total attempts within a skill, i.e. attack, service, blocking, setting, passing, and defence. Stroll down or click on the link below for the specific performance indicator type.
*** Update 19 December 2023 ***I’ve updated this blog post to include Expected Values and Actual Values Over Expected. I also decided to include the sideout % and break point % because it a common performance indicator and it may need some explanation in the Expected Values section, I also decided to rearrange the order from simple to advanced. *** Update 19 December 2023 ***
Simple Performance Indicators* * * * * * *
Intermediate Performance Indicators* *
Advanced Performance Indicators* *
Perfect Percentage
Definition: The Perfect % is the percentage of total attempts that result in a perfect action
Calculation: Perfect % = Perfect Actions / Total Attempts
Example: Kill % = Kills/ Total Attack Attempts Perfect Reception % = Perfect Receptions / Total Reception Attempts
Pros: * Highlights the perfect actions, especially point-scoring actions * Commonly used * Easy to understand * Can be used for any skill
Cons: * It ignores all other attempts, especially errors. A player may have a high Kill % but if they have a higher Attack Error % then they are actually hurting the team. * Perfect actions need to be recorded, which you may not do for reception or defence * Total attempts need to be recorded to calculate this performance indicator
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In-Play Percentage (or Error Percentage)
Definition: The In-Play % is the percentage of total attempts that result in the continuation of play. This is the inverse of an error percentage.
Calculation: In-Play % = 1 – (Errors / Total Attempts)
Example: Dig In-Play % = 1 – (Dig Errors/ Total Dig Attempts) Attack In-Play % = 1 – (Attack Errors/ Total Attack Attempts)
Pros: * Positive spin on the error percentage * Easy to understand * You may want to play players who can keep the ball in play – somebody else can get the kill
Cons: * It ignores all other attempts, especially perfect actions, e.g. what was the quality of the dig? * Total attempts need to be recorded to calculate this performance indicator
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Positive Percentage
Definition: The positive % is the percentage of total attempts that result in either a perfect or positive action
Calculation: Positive % = (Perfect Actions + Positive Actions) / Total Attempts
Example: Positive Pass %= (Perfect Passes + Positive Passes)/ Total Attack Attempts Positive Serve %= (Aces + Positive Serves)/ Total Serve Attempts
Pros: * Useful if the perfect and positive actions are similar in their outcome, e.g. the middle player is still available to attack after a perfect and positive pass * Works best with defensive skills
Cons: * Doesn’t really work with point-scoring skills as the perfect action, i.e. a point scored, is not equal to a positive action, i.e. no point scored * Actions need to be graded to have a positive action, which is time-consuming and can decrease objectivity in grading * It ignores all other actions that are not perfect or positive * Total attempts need to be recorded to calculate this performance indicator
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Efficiency Ratio
Definition: The number of perfect actions for every error
Calculation: Efficiency Ratio = Perfect Actions/ Errors
Example: Point-Scoring Efficiency Ratio = Points Won/ Points Lost Serve Efficiency Ratio = Aces/ Service Errors
Pros: * Considers both point scoring and point losing actions, both critical for success in volleyball * You don’t need to record every attempt, just the perfect and error actions only * Will create bigger differences compared to the efficiency pct. for skills, especially useful if perfect actions and errors do not occur too frequently, e.g. ace and service errors * Points efficiency ratio is highly correlated to success in volleyball
Cons: * Does not take into account total attempts, e.g. two players could have the same efficiency ratio but if one player only needed half the attempts compared to the second player then they did twice as good * You will get division by zero errors if you have either 0 perfect actions or 0 errors, a particular problem with blocks and serves
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Per Set Average
Definition: The average number of actions, usually perfect or errors, performed on a per-set basis
Calculation:Per Set Average = Actions (Perfect or Error) / Total Sets Played
Example: Aces Per Set = Aces/ Total Sets Played Digs Per Set = Digs/ Total Sets Played
Pros: * Commonly used and easy to understand * You don’t need to record every attempt
Cons: * You need to record the total sets played to calculate this performance indicator * Does not create a good level playing field as it does not take into account total attempts properly, e.g. middle players will usually have a lower kill per set average compared to outside hitters because they had fewer opportunities to attack * You can read more on this link on why I don’t like per-set averages
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Differentials
Definition: The difference between the total perfect actions and total errors
Calculation: Differential = Perfect Action – Error
Example: Points Won-Lost Differential = Points Won/ Points Lost
Pros:* Commonly used and easy to understand * You don’t need to record every attempt, just the perfect and error actions only
Cons: * Does not take into account total attempts, e.g. a player cannot achieve a high differential if they had limited opportunities * You can’t scale the data, e.g. a player has a +51 points won-lost differential for the season – it’s a high number but how good is it? * You can read more on this link on why I don’t like using differentials
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Sideout %/ Break Point %
Definition: Sideout % is the percentage of rallies won as the passing team. Break Point % is the percentage of rallies won as the serving team.
Calculation: Sideout % = Rallies Won as the Passing Team/ Total Opposition Service Attempts Break Point % = Rallies Won as the Serving Team/ Total Service Attempts
Pros:* Commonly used and easy to understand * This can be calculated from the score sheet
Cons: * You can only use it for the team and not for the individual player * Sideout % and Break Point % are not fully within the team’s control, e.g. the team could have a high sideout % simply because the opposition team made a lot of service errors * You can read more on this link on why I don’t like using Sideout % and break point % in my analyses
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Efficiency Percentage
Definition: The efficiency % is the percentage of total attempts that result in a net of perfect actions, since every perfect action is cancelled out by an error. To put it another way, it is the difference between a perfect % and an error %.
Calculation: Efficiency % = (Perfect Actions – Errors)/ Total Attempts
Example: Hitting % = (Kills – Attack Errors)/ Total Attack Attempts Points-Scoring Efficiency % = (Points Won – Points Lost)/ Total Point Scoring Attempts
Pros: * Considers both point scoring and point losing actions, both critical for success in volleyball * Hitting % and Point-Scoring Efficiency % are both highly correlated to success in volleyball * They are the most effective performance indicators in my opinion
Cons: * Does not work well if there are few point-scoring actions and errors, such as the block * Does not work well with non-scoring skills, such as reception and digs * It ignores all other actions that are not perfect or errors * Total attempts need to be recorded to calculate this performance indicator
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Weighted Average/ Rating
Definition: The weighted average/ rating is the weighted average or rating of the skill performed, where each action is weighted according to its importance, e.g. perfect passes have 3 points in weight, reception errors have 0 points in weight
Calculation: Weighted Average = (Sum of Variable Actions * Weight)/ Total Attempts
Example: Pass Rating = [(Perfect Pass * 3) + (Positive Pass * 2) + (Negative Pass * 1) + (Overpass * 0.5)]/ Total Pass Attempts Attack Rating = [(Kill * 4) + (Positive Attack * 3) + (Negative Attack * 2) + (Rebounded Attack * 1) + (Attack Block Killed * 0.5)]/ Total Attack Attempts
Pros: * Every action is taken into consideration * Can be applied for any technical skill
Cons: * Difficult to understand for players and coaches in terms of level of performance, e.g. is an attack rating of 2.79 good or bad? * Given weights are arbitrary, e.g. why isn’t a passing error worth -3 points instead of 0 points, since the player lost the rally? Click on this link for more information on this. * Every action needs to be graded, which is time-consuming and can decrease objectivity in grading
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Expected Values
The Expected Value is what you would expect to happen in a given situation, and it is usually related to point scoring. For example, the Expected Sideout % is the expected sideout % (or rally win rate) to be for a given quality of pass. The Expected Value is essentially a weighted average but with appropriate weights. Read more about it on this link.
Calculation: Expected Values = (Sum of Variable Actions * Expected)/ Total Attempts
Example: Expected Sideout % = [(Perfect Pass * Sideout % After Perfect Pass) + (Positive Pass * Sideout % After Positive Pass) + (Negative Pass * Sideout % After Negative Pass) + (Overpass * Sideout % After Overpass)]/ Total Pass Attempts Expected Break Point % = [(Ace * 100%) + (Opposition Overpass * Break Point % After Opposition Overpass) + (Positive Serve * Break Point % After Positive Serve) + (Negative Serve * Break Point % After Negative Serve)]/ Total Serve Attempts
Pros: * Every action is taken into consideration * Every action is weighted appropriately * Can potentially relate all technical skills to a single metric related to point-scoring
Cons: * Every action needs to be graded, which is time-consuming and can decrease objectivity in grading * You need a ton of data on all the teams (not just your team) in your competition (e.g. you can’t use the sideout rates in the Olympics for your local team as they won’t be the same) to determine what the actual sideout % is after a perfect pass, after a positive pass etc., which is unlikely you will have
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Actual Values Over Expected
Actual Value Over Expected, or Expected Values Added, is the difference between what actually happened and what you expected to happen in the same given situations. That is, how well did you perform over what was expected. Usually written as Actual Value (± Expected Value). Read more on this link.
Calculation: Actual Value Over Expected = Actual Value – Expected Value
Example: Hitting % Over Expected = Actual Hitting % – Expected Hitting % = [(Actual Kills – Actual Attack Errors)/ Actual Total Attack Attempts] – [(Expected Kills – Expected Attack Errors)/ Expected Total Attack Attempts]
Pros: * Same as Expected Value * It creates an even better level playing field to compare some performances, e.g. you can use Hitting % Over Expected values to compare middle players’ hitting % to outside hitters (see link to read more)
Cons: * Same as Expected Value * Calculating the Actual Value Over Expected can get complicated to determine, export, and calculate, depending on how specific the situation you want it to be. In my Hitting % Over Expected study, I had 96 unique attack situations that I had to determine the hitting % for, create a worksheet to export all that data, and write out a very long formula to calculate the Expected Value
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Final Thoughts
These are the common types of performance indicators used in volleyball. There are other performance indicators out there, e.g. the Aggression % or Attacks per Defensive Opportunity, but to cover them would take too long. These are the common types of performance indicators used in volleyball. There are other performance indicators out there, e.g. the Aggression % or Attacks per Defensive Opportunity, but to cover them would take too long.
What performance indicators you can use will depend on which ones you want to use (some performance indicators are better than others), the amount of work needed to collect the stats to calculate the performance indicator (a weighted average is great but you’ll need to grade each action quality, which requires a lot of work to record and to be consistent at it) and how easy it is to understand for you, the players and the coach (I once rated the attack on an 11 point scale, so it was meaningless to the coach and team when I said a player had an attack rating of 7.84). What performance indicators you can use will depend on which ones you want to use (some performance indicators are better than others), the amount of work needed to collect the stats to calculate the performance indicator (a weighted average is great but you’ll need to grade each action quality, which requires a lot of work to record and to be consistent at it) and how easy it is to understand for you, the players and the coach (I once rated the attack on an 11 point scale, so it was meaningless to the coach and team when I said a player had an attack rating of 7.84).
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