For those of you that can remember way back to the start of October, before the season even kicked off, I posed a question in Quick Hits that I’ve been unable to get out of my head:
If Defender A blocks 50 shots in a season and Defender B blocks 200 shots in a season, who is the better defenseman (assuming identical ice time and deployment)? And does your answer change if we know that Defender A’s blocks all resulted in recovery of possession and all of Defender B’s blocks went back to the opponent?
I thought it would be a cool weekend project to explore. I didn’t realize it would actually be several weekends, and potentially many more still.
The Problem With The Problem
One of the things that’s taken so long is figuring out exactly how to measure transition in hockey. That’s essentially what the above thought exercise is asking – can we measure if one defender is any better at using off-the-puck activities, like Blocks or Hits, not just to disrupt a play but to actually create a change in possession that should reduce shot attempts against.
To be clear, we aren’t talking about a Takeaway. That’s a very specific event that’s typically the result of stickwork, where the player being credited with the takeaway almost always comes away with the puck. Nor are we talking about forcing a Giveaway, typically resulting from an errant pass or mishandling of the puck. And if you look at the Play-by-Play game breakdowns on the NHL app (thanks to JJFromKansas for suggesting this as a confirmation check), you can see that Takeaways and Giveaways are tracked separately from and are not listed with the same time stamp as (or even in conjunction with) a Block or Hit. For example:
In our game against the Islanders on October 30th, Jake Walman is credited with blocking a Casey Cizikas shot with 17:10 left in the 1st period according to the Play-by-Play log. The next event tracked is a Dylan Larkin shot on Ilya Sorokin 11 seconds later. While we know a change in possession happened, we don’t have confirmation that the blocked shot was the cause of that change (the same problem exists with Hits, but more on that later). We have the same complication with 3:41 left in the 2nd and a 20-second gap until the next Play-by-Play event.
So, we know that there’s an event gap where something important – a Possession Event – is happening, but is not being tracked or otherwise accounted for with something like a Takeaway or Giveaway. Because there’s no statistic kept for this type of event, it’s difficult to measure without going back and watching game footage to manually track as an independent measurable. The closest we can get without that level of effort is relating a player’s blocked shots to their Corsi-Against numbers.
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