[M T]

Why do you subtract an individual's digable balls from the denominator?  The number you are looking for is the percent of diggable balls that a player digs, as well as the percentage that are dug "in system".  So, based on your numbers, Hentz dug 539/(1307+1518) = 19% of all diggable balls, while Seimet dug 768/(1436 + 2225) = 21% of all diggable balls.
...

There really is no easy to calculate statistic that will do a libero justice.  It's sort of like trying to measure defense in baseball using just fielding percentage.  Basically you would need an advanced stat akin to some of the advanced stats that seek to determine the number of runs through defense.

You're  right.   I should not have subtracted their digs.

Yes, the point was that while some  factors could be accounted for, the best statistic I could come up with, wasn't sufficient to highlight how good Hentz is.

[M T]

Why do you subtract an individual's digable balls from the denominator?  The number you are looking for is the percent of diggable balls that a player digs, as well as the percentage that are dug "in system".  So, based on your numbers, Hentz dug 539/(1307+1518) = 19% of all diggable balls, while Seimet dug 768/(1436 + 2225) = 21% of all diggable balls.
...

There really is no easy to calculate statistic that will do a libero justice.  It's sort of like trying to measure defense in baseball using just fielding percentage.  Basically you would need an advanced stat akin to some of the advanced stats that seek to determine the number of runs through defense.

You're  right.   I should not have subtracted their digs.

Yes, the point was that while some  factors could be accounted for, the best statistic I could come up with, wasn't sufficient to highlight how good Hentz is.