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The Perceived Value of Blocked Shots

Ari Yanover
8 years ago
[Editor’s note: This is a guest post from clib542, who has been nerding it up over on Twitter under the same username. I asked him if he wanted to put his findings into a full-fledged article, and here we are!]
It is no secret that the Calgary Flames are good at blocking shots. There is more to it than just getting in front of the puck; it takes courage and grit. The players who are best at blocking shots are the heart and soul of the team and are often leaders on and off the ice. 
You could argue that there is an art to blocking a shot, involving timing and technique. I think it would be safe to say Bob Hartley expects the players to block shots, and it is used as a defensive strategy. For every shot blocked, it is one fewer shot the goalie needs to save. 
However, is putting yourself in front of a 100mph shot worth it? Every year there are countless injuries due to blocking a shot. Unless a player dives across the crease, or knocks a puck off the goal line, preventing a sure goal, how much value is there in blocking at shot?

Anatomy of the Shot Block

Not all shot blocks are created equally. Some players get in shooting lanes and take the puck off their skates or shin pads. Others leave the ice to dive in front of the puck, ideally feet first, but players have been known to go head first. Shots can also be blocked by getting a stick in the way to deflect the puck out of play or away from the net (if not into their own goal). 
Some of these techniques are better than others, but I am not going to look at that.

Blocking Shots Stats

Since the beginning of the year, I decided to track the differences in the events after a blocked shot and not blocking the shot (shots on goal and missed shots). To make it simple enough to follow, and the ability to use the NHL.com – Full Play by Play – Game reports, I separated the events into four categories.
  1. Allowed another shot (shot on goal, missed shot, or another blocked shot)
  2. Stoppage in play (by goalie or puck out of play)
  3. Possession not changed (event happened in defensive zone)
  4. Possession changed (event happened in neutral/offensive zone)
The last two categories are not as important as the first two as there are so many different possibilities. 
Essentially, in the defensive zone, there is a puck battle where either team could come away with the puck. Events in the neutral or offensive zone can be anything from a battle for the puck to an attempted shot by the Flames.
After 17 games – not including last night’s affair against the Capitals – Flames have blocked 284 shots, and allowed 614 shots towards the net.
After a Blocked ShotAfter Allowing a Shot
1. Another Shot35.6%33.9%
2. Stoppage in Play21.5%33.7%
3. Possession not Changed19.4%14.7%
4. Possession Changed23.6%17.8%
Again, try not to put too much into the bottom two categories because of the many different outcomes. 
The numbers change between blocking a shot and not blocking, but the differences in percentages is both are around 3-4. 
What stands out to me the most is the first category: allowing another shot. According to the numbers, the Flames are slightly better off when they do not block the shot than when they do. Albeit, the difference is very small, but it makes you think if putting an emphasis on blocking shots is worth it. 
It is too simple just to say 10% of blocked shots would have resulted in goals (based on save percentage), as there is no way in knowing if the original shot would have been on net, as well as other factors impossible to calculate working with hypotheticals.
To compare with the Flames, I also decided to look at a team who is at the bottom of the league in blocking shots. I do not follow New Jersey too closely, but being at the bottom of the league, this probably means their defensive strategy does not start with blocking shots.
After 16 games, Devils have blocked 204 shots, and allowed 573 shots towards the net.
After a Blocked ShotAfter Allowing a Shot
1. Another Shot31.4%26.9%
2. Stoppage in Play16.2%33.7%
3. Possession not Changed24.0%22.3%
4. Possession Changed28.4%17.1%
There are some clear similarities and some clear differences here. When not blocking a shot, both the Flames and the Devils get a whistle 33.7% of the time. While still high, the Devils do a better job not allowing another shot after the original block and are favourably better when allowing the shot through. Granted though the Devils have Cory Schneider and not Karri Ramo starting most of their games, it would appear they allow the goalie to make the save.
In an article in the Boston Globe last year, Tuukka Rask said he would prefer the defense to be in position to clear rebounds or take the man than go down to block the shot. Dougie Hamilton mentioned something similar when talking about the differences between the systems of Boston to Calgary in Elliotte Friedman’s 30 Thoughts
Based on the numbers, it is not hard to support these ideas. I am not saying Flames should stop blocking shots, but to base your defensive strategy around it does not give the team any statistical advantages.

The Dangers of Blocking a Shot

Take a look around the league. Players such as Paul Stastny, Dwight King, and David Pastrnak are all currently injured due to blocking a shot. In recent years, Giordano, Brodie, and Bouma have all lost time because of an injury caused by the puck. Intentionally or not, blocking a shot can result in an injury. When a player is out of position attempts to block a shot, they become even more vulnerable as equipment does not cover all areas of the body. 
Bob Hartley does not seem to be too concerned. In a Calgary Sun article before the season started, Hartley acknowledged the possibility of injury, but implied potentially stopping a goal by blocking a shot was a better option.

Value in Blocking Shots

When it comes to the “eye test”, blocking a shot is right up there. It is a noticeable event, which if everything goes right, saves a goal against – then leads to a goal for. Players are praised by coaches and the media for sacrificing their bodies for the team. Defensemen get labelled as good defenders even though the reason for the high number of blocked shots is because they allow a lot of shots against.
If the purpose of blocking a shot is so your goalie does not have to make a save, it seems meaningless you would employ a strategy which allows more shots after the initial one than if they let the goalie make the original save. Maybe a better strategy would be to get into the shooting lanes to prevent the shot in the first place. 
As much as the Flames goalies are not making the save this year, the team should trust them to do their job. Let the goalie see the puck and clear the rebound if there is one. 
I will continue track the events after a shot for the rest of the season, but the numbers have levelled off in the last couple of games.

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