Today, John Tortorella had a question about power plays.
It’s certainly a reasonable thing to wonder. It also seems like the kind of thing that, you know, your analytics person or department could quite easily figure out. But hey, the “let those Twitter guys figure it out” approach works as well I guess.
Anyway, I took the bait, partially because I am a power play fiend and partly because I’ve become more and more interested by faceoff impact. So I figured out the numbers. It’s important to note that NHL scorekeeping can be sketchy. Each scorer may have a different definition of a faceoff win, which can lead to some problems. But at this point, it’s what we have, so let’s take a look.
I used data from the last two full seasons, 2013-2014 and 2014-2015, because I wanted situations that followed the league’s rule change to have (essentially) all power play start in the offensive zone. I also used exclusively 5v4 data to keep things clear. The sample size is around 15,000 faceoffs, which makes sense if you consider that each team gets just over three power plays per game.
3 power plays * 82 games * 30 teams * 2 seasons ~ 15,000.
So here are the results:
Overall 5v4 PP% = 18.32%
5v4 PP% when you win the first faceoff = 20.53%
5v4 PP% when you lose the first faceoff = 16.21%
So overall, there is a impact, but it’s small. You’ll score about a goal more every 20 power play opportunities if you go from losing EVERY opening power play faceoff to winning EVERY one. It’s not something that I would lose too much sleep over, although to be fair, every little thing counts.
That’s not a small difference at all. Winning as opposed to losing the opening faceoff increases the average success rate from 16% to 20%, in other words your chance of scoring is boosted by 25% (the extra 4% likelihood is 1/4 of your original 16% likelihood).
It only looks like a big difference if you choose to frame it as such. The boost is small enough that in the long run it doesn’t matter much. That’s especially true since differences in faceoff% aren’t that big; the worst faceoff takers in the league win 40% and the best win 60%. That means that if a team replaced the league’s worst faceoff taker with the league’s best on every single one of their powerplays, the difference would be 2 goals over the course of an entire season.
Really nice post, Arik. I like these short pieces that can dig into a question that traditional media types would only speculate on. I also think there’s a lot of work to be done to better understand special teams play, and I’m excited to see what you come up with moving forward