Mark Lebedew once posed a question on Facebook. It went like this:

What does number of transition attacks divided by number of serves measure? If anything.

After a bit of discussion, Mark made the following clarification:

So now I have removed service errors and direct block points. I am left with transition attack attempts divided by number of times the attack gets past the block. What am I measuring now?

So we have this formula:

Transition Attacks / (Opponent Attacks – Blocks – Hitting Errors)

My response at the time was to say that broadly speaking you are measuring dig %. After all, you must dig the ball to get a transition swing. If you consider Transition Attacks to be something other than simply playing the 3rd ball over the net, then you are effectively deriving a “good” dig %. The first requirement of attacking back at the opposition is a settable dig (or, in theory, hittable on 2).

I’d be curious to hear what you would say in response to Mark. Beyond that, though, I wanted to point out the importance with regards to statistics of actually understanding what you’re measuring. It might not be the same as what you think you’re measuring.

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John Forman

John is currently the Talent Strategy Manager (oversees the national teams) and Indoor Performance Director for Volleyball England, as well as Global Director for Volleyball for Nation Academy. His volleyball coaching experience includes all three NCAA divisions, plus Junior College, in the US; university and club teams in the UK; professional coaching in Sweden; and both coaching and club management at the Juniors level. He's also been a visiting coach at national team, professional club, and juniors programs in several countries. Learn more on his bio page.

### 15 replies to "What is this statistic really measuring?"

• Alexis

I think ‘Defensive Efficiency’ might be a good way to look at that stat. It is more than just dig % because good block touches are included, not just balls that are not touched and are dug.

Having said this – I’m not sure it provides much (if any) more information than looking at transition hitting stats.

• John Forman

When I first made this observation, Mark didn’t like it because he hates counting digs. 🙂

I’d make the point that balls off the block still count as digs, but I can go with Defensive Efficiency since it should to at least some extent capture the effectiveness of your floor defense and your blocking scheme.

I would suggest that it does actually offer something above and beyond transition hitting stats because it determines how many transition hitting opportunities the team gets. In theory at least, more opportunities means more transition points. To the point Mark made at his FIVB clinic in June, though, if getting those extra opportunities actually reduces the efficiency of the transition attack (say be eliminating the pipe option) then more transition swings won’t actually increase points scored.

The tricky bit is comparability. You’d need to hold something constant – either quality of the opposing attack or the service – to be able to make any real usable comparisons.

• markleb

It is not a dig%, because it also includes free balls created and overpasses attacked.
It is different to transition hitting stats because they only measure hitting. They could infer quality of defence but not doesn’t include missed opportunities.
I am kind of thinking that this number could be used in conjunction with the trans hitting percentage.
I am trying to get to something that measures the whole defensive package. And I specifically don’t want to use digs because I don’t trust those stats.

• John Forman

Fair enough on the freeball/overpass thing – but do you really want to include them? Doing so seems likely to be more about judging serving effectiveness than defense.

Also, if you want something that includes “the whole defensive package”, shouldn’t that include blocks as well?

• markleb

I was thinking exactly that as I was writing those words. In which case it has to include aces too.
So that leaves us with %aces + %blocks (break point phase) + (some version of this number)
The closer to 1 the better.

• John Forman

Going back to the FIVB seminar discussion, if the objective of your defense is to score a point, then to truly judge the defensive effectiveness you should take transition points scored in the break point phase divided by total opponent attacks (ideally just legitimate “good” attacks to remove the impact of serving effectiveness from consideration). Points scored I think should include blocks and hitting errors. I include the latter because at least when you reach a sufficiently high level errors are more a function of attempting to beat the defense than basic mechanical mistakes. If you’re doing a good job of taking away defensively what the hitter wants to do, at least in theory you should see more blocks and HEs, plus you should be able to dig more balls better.

• markleb

I think I want to include serve effectiveness, because that is also part of it.
But I’m not sure.
I wanted attempts instead of points scored in transition, because I wanted to exclude the quality of the attack. To get closer to the defensive component. That is why I mentioned to Alexis’ comment that I would use it in conjunction with Transition attack percentage. If one is higher or lower that implies where the problems lie.

• John Forman

I would think if you want to look at serving effectiveness, you can just look at something that compares aces and out-of-system balls to errors and in-system ones.

After that you could look at your defensive effectiveness for both in- and out-of-system plays using something like (blocks + opponent HEs + transition swings) / opponent attacks. That would give you a nice level of granularity for judging your defense in different phases. Plus, in this way you could also include secondary phase defense.

• Alexis

combining with trans hitting makes sense (I was actually going to mention something along those lines in my last comment).

the trick would be to combine them, making sure that you can’t counting the same thing twice.

oh – and you need to account for ball handling errors and or direct setting errors. maybe

• Michael

Take 2 teams with weak (non-existent) attacks and good defense and it would seem to me that you are basically measuring rally length. Unless I have missed something in the translation, which is highly possible!

• John Forman

Hi Michael – I believe Mark was only considering the initial defensive phase following serve (first transition opportunity), but depending what you’re after you could extend it to include all transition situations.

• Michael

if we are only measuring the number of times a serve comes over and how many times the ball is attacked past the block, then you are measuring how many times your team does not get blocked during service reception.

As one of the statistical geniuses once asked, “How does this impact on winning?” I would be mostly at a loss to see how this is any more relevant than just looking at your opponent’s pure number of blocks in the match to tell you if you are getting blocked too often.

Do you see something else?

I assume it might assist you in determining whether you get blocked more while in system or out of system?

• John Forman

I think you’re looking at the wrong end of things – at least from the perspective of the original question.

What Mark is looking at is the number of times the opponent’s attack gets past your block (defensive opportunities) compared to the number of times you are able to generate an attack in return subsequently.

• markleb

Thanks, John. Spot on.

• Michael

In that case, I would agree that you are basically looking at # of digs (if your dig stats include all balls crossing the net that are passed well enough to allow an attack to occur, as a dig)

Yes???