How Should I Measure Errors?

It is conventional wisdom in volleyball, and indeed in most sports, that the team that makes the fewest errors should win. Many maintain that attack efficiency, and therefore implicitly attack errors, are the key determinant to success. Conversely many say that a minimum number of service errors is required in order to develop enough pressure to win.

However to the best of my knowledge noone has ever looked at other kinds of errors or how the total number of errors might influence the outcome.  It sounds like something we should know about. 

The first problem is how to measure errors. Total errors might be one way to go if we are looking at indivdual sets. But in general totals, or even per set averages, are not very good because they don’t take into account number of opportunities. Therefore the obvious measurement is a percentage of total contacts. But that ends up being a very small number. And how do you include block attempts. 

The number I have started working is errors per 100 rallies. This ends up being a quite nice number. In my league the average is between 12 and 16. Conversely the number of points ‘won’ is between 30 and 36. I haven’t done any serious analysis but eyeballing it, it looks like there might be something there.

My question is: Is this a reasonable way to measure errors? Can you think of a better way?

All comments welcome.


5 thoughts on “How Should I Measure Errors?

Add yours

  1. A further complicating factor is the situation of the error. i.e. a player attacking a ball out of the back row on an out of system situation ( on coaches instructions) compared with simply free balling it over the net which has a high likelihood of a point loss but is not stated as an error.
    A player called for lifting when diving to retrieve a ball off the block would result in an error, yet the point was in all reality lost. Filtering these errors may be required to give a clearer picture of errors with/without “worthy errors”.


  2. It would be interesting to know if the errors go up when points go up, or if they go down. More aggressive play might include more errors; it may also lead to more points. Somewhere there might be a sweet spot, where a certain number of errors may lead to a certain number of points.


  3. In terms of ball-handling errors with reference to those called on plays made on very difficult balls, I’d venture to say those are infrequent enough not to really need to be filtered out.

    The bigger question for me is whether you focus on unforced errors (those that show up directly on the stat sheet – hitting, serving, blocking, ball-handling) or on other types of errors. In the latter category I included errors in decision-making and “forced” errors which are technical mistakes when attempting to dig, receive serve, and the like. Both require more detailed analysis, of course.


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