Blocked shots are a bit of a contentious topic in the world of hockey statistics. Traditional, old-school thought is that blocking shots is a sign of grit and toughness, and is necessary to win hockey games; the more blocked shots, the better. Earlier this season, Don Cherry called out the Vancouver Canucks for not “paying the price” because they were frequently blocking fewer shots than their opponents.
Meanwhile, the proponents of advanced statistics claim that a higher number of blocked shots is usually a bad sign: if you need to block a shot, not only do you not have the puck, the puck is in your end of the ice rather than in the offensive zone. This school of thought would point out that the Canucks don’t block a lot of shots because they are one of the better puck possession teams in the league.
The conflict between these two opposing viewpoints came to a head back in 2010 on the March 27th edition of Coach’s Corner. Ryan Johnson, the personification of the blue collar, hard-working “good Canadian kid” that Don Cherry loves so much, had the lowest Corsi rating of the season. Cherry, predictably, flipped out, saying “this shows how stupid the Corsi thing is.”
Before launching into the highlight package, Cherry turned to Ron Maclean and asked “Do we got him blocking shots?”
That was the key issue for Cherry and it was also a bit of a silly question: of course they had video of him blocking shots. The only thing Johnson ever seemed to do in the NHL was take faceoffs and block shots. He was last in Corsi because he was exceptionally terrible at moving the puck into the offensive zone and keeping it there, so he was always in the defensive zone throwing his body in front of the puck.
Here’s the issue: it’s not an either/or situation. Blocking a shot is not inherently negative. In general, if an opponent is shooting the puck and you have the opportunity to block the shot, you do so. At the same time, blocking a shot is not inherently positive. Preferably, you are the one shooting the puck rather than blocking it.
Harrison Mooney over at Pass it to Bulis has pointed out that both good and bad teams block lots of shots and both good and bad teams block few shots. It’s not as simple as saying that teams that block a lot of shots are terrible and those who block few shots are good.
So there has to be a better way to measure blocked shots that takes puck possession into account. Derek Zona, of the Edmonton Oilers’ blog Copper & Blue, wrote a post last month that suggested the best way to do this is to measure the percentage of shots a player blocks rather than the total.
I think there’s a lot of merit to this approach, as it eliminates the influence of a higher number of shots allowed. An extra benefit is that it allows you to compare between players with differing number of games played, which is useful with players who block shots as they seem to frequently get injured.
It also makes intuitive sense that the player who blocks the highest percentage of shots is the best shot blocker, which is nice upshot when a lot of advanced statistics can seem overly convoluted.
There are a couple flaws: since what is and is not a blocked shot is subject to arena bias, this is not a perfect comparison between players across the league. A player whose home arena regularly overcounts blocked shots will have an artificially higher percentage of shots blocked as well. Also, Zona’s numbers, as well as the one’s I am going to use, are exclusively from even-strength, 5-on-5 situations. While this is a benefit in that it makes for an even playing field across the league, it removes the game situation in which a blocked shot is most highly prized: the penalty kill.
Expanding this measurement to include shorthanded situations or measuring them separately seems like the obvious next step, but I unfortunately do not have access to the data at this time. Still, looking at even-strength numbers still has plenty of potential for insight. Players who are good at getting into shooting lanes to block shots should be able to do so at both even-strength and on the penalty kill.
Here are the top ten defencemen in even-strength blocked shot percentage this season (minimum 10 games played):
|Name||Pos||Team||GP||ES Shot Attempts Against||ES Blocked Shots||ESBS%|
None of the names that appear on this list are particularly surprising. Each of them has been individually lauded for their ability to block shots in the past. What’s interesting is the players who are not on this list.
Mark Stuart of the Winnipeg Jets is currently leading the league in blocked shots. Measuring him by percentage, however, drops him down to 27th amongst NHL defencemen. In his defence, he plays a lot on the Winnipeg penalty kill and only 64 of his 105 blocked shots are at even-strength. Josh Gorges, third in the NHL, drops down to 18th, which is not too terrible.
The big drop comes from Dan Girardi of the New York Rangers, who is fifth in the league in total shots blocked, but takes a nose dive down to 86th amongst defencemen in even-strength blocked shot percentage. While he blocks a large number of shots, the Rangers’ opponents take a lot of shots when he is on the ice.
Unsurprisingly, Girardi has a negative Corsi rating. His high number of blocked shots is more indicative of his relative inability to transition the puck into the offensive zone rather than of an above-average ability to block shots.
On the other hand, Niklas Hjalmarsson, who is second in the NHL in blocked shots, is first by even-strength blocked shot percentage. Of the 544 shot attempts made at even-strength against the Blackhawks while he is on the ice, Hjalmarsson has blocked 75 of them. He also boasts a positive Corsi rating, which correlates nicely with this result.
Hjalmarsson comes by his high blocked shot totals because he is legitimately good at getting into shooting lanes, and not just because he happens to be on the ice when the opponents are getting a lot of shots. I feel comfortable saying that Niklas Hjalmarsson is the best shot blocker in the league this season.
Here are the top ten forwards in even-strength blocked shot percentage (again, 10 game minimum):
|Name||Pos||Team||GP||ES Shot Attempts Against||ES Blocked Shots||ESBS%|
|4||Stephane Da Costa||C||OTT||22||179||13||7.27%|
Since forwards tend to block fewer shots overall than defencemen, we run into some sample size issues. Such is likely the case with Andrew Ebbett, who has only blocked 8 shots at even-strength in his 13 games played. While this is a decently high percentage of the total shot attempts against the Canucks while he is on the ice, it’s far too small a sample to say for certain whether he has an above average ability to block shots.
Players in the top ten in total blocked shots that remain in the top ten in terms of percentage are Boyd Gordon, who leads all forwards in total blocks, Tim Connolly, and Michal Handzus.
Brooks Laich suffers the most among forwards by this measurement, falling from 8th to 60th, blocking 4.86% of total shots attempted when he is on the ice. His Corsi rating has dropped to below even for the first time in his last five seasons, mainly because he’s starting more often in the defensive zone than in the offensive zone, a situation he hasn’t really had to deal with before. He doesn’t appear to be handling it particularly well.
Let’s come back to Don Cherry’s favourite player, Ryan Johnson. One of his main claims to fame was when he led all forwards in blocked shots in 2007-08 with 105. At even-strength, at least, the evidence suggests that he wasn’t as good at blocking shots as advertised: he blocked 5.78% of all shot attempts while he was on the ice, which would place him 35th amongst this season’s forwards.
Johnson blocked a large number of shots at even strength that season simply because he couldn’t keep the puck out of the defensive zone. By looking at blocked shot percentage rather than just blocked shot totals, we can get a truer picture of which players in the league are better at blocking shots.