Let’s talk about shot blocking

Updated: May 29, 2013 at 3:38 pm by Cam Charron

It’s not that blocked shots aren’t important, it’s that the team with the most blocked shots isn’t necessarily the best team at shot blocking—the team with the most blocked shots is often the one trying to clear the puck out of its own end. Like in that PK above. It’s an excellent shift from Tyler Carroll, but I’d bet that Guelph would rather not be down 3-on-5 in that situation.

So a new statistic has popped up: “Percentage of shots blocked” and it’s a little dicey as well. Generally speaking, it’s just not good to block a lot of shots or to be in situations where you have to block a lot of shots. “Percentage of shots blocked” has been kicking around but I’ve seen no evidence that it’s a repeatable statistic that correlates with winning.

Eric T. had several interesting tweets today. I’m trying only to copy-paste the relevant stuff, but go to his feed from the last 12 hours ever and you’ll find some great stuff:

Now, why do you suppose that is? How come the defencemen that block the highest percentage of shots are much, much worse on paper than the defencemen that block the lowest percentage of shots?

This is something I kicked around last summer and may as well publish a few results. The answer is that if you flip it around, and measure the players that have the highest percentage of their own shots blocked, you’d find that it’s almost exclusively defencemen.

I broke down a list of the 500 players who took the most shot attempts in 2011-2012 from Behind the Net. Of those 500 players, 187 were defencemen. Those defencemen had a shooting percentage of 4.0% while forwards had a shooting percentage of 10.1%.

So far, nothing interesting or mind-blowing. Everybody knows that forwards are better shooters than defencemen. They shoot from closer, they get more breakaway opportunities and far more scoring chances.

But if you break down “percentage of attempts blocked”, all but one of the players outside a single standard deviation from the median was a forward: Blake Comeau had 34.1% of his attempts blocked.

Break it down:

  Shooting % % of Attempts Blocked
2+ standard deviations higher 3.8% 42.8%
1 standard deviation higher 3.9% 35.8%
With 1 standard deviation 9.2% 24.5%
1+ standard deviation lower 9.9% 15.8%

Conclusion? Shots that are blocked are generally coming from well out, from shooters who score less than 4% of the time anyway. You’d need to block 25 shots before saving a goal, all while hoping that you aren’t screening your goaltender or deflecting a puck. I’m guessing that the players who get in shooting lanes for point shots to block them end up costing their teams more.

Perhaps we could break down the “percentage of attempts blocked” even further and look at “percentage of forward attempts blocked”. I don’t have the capability for that, but it seems like there’s more value in looking at players who block shots closer to the net. Three or four times a game a shot from a good scoring area is blocked and we don’t count it as a chance.

But perhaps somebody with some programming knowledge could…