Does Blocking shots at a higher rate help win games?

[habsfanatics*]

What's interesting is that blocking shots doesn't seem to have much, if any effect on goals against.

You'd think teams with the most blocked shots would have at least like 10% less goals against or something, but I guess what this really shows is that by blocking more shots, a team is also giving up more shots, which in turn results in more goals against. Plus blocking shots often just returns the puck to the player(s) who had control of it before anyways, so they're just going to keep shooting until they get one on.

Obviously there are going to be instances where a blocked shot actually does save a goal, but apparently not enough to make a big impact

I don't see how one would come to this conclusion, if you're blocking more shots, chances are you giving up more too. The amount of events going towards your net is what is driving up the shot blocking numbers and that is why they have no correlation with winning, in many instances the opposite, it only makes sense.

 

[boredmale]

more blocked shots = greater chance of injury

While it's commendable that somebody sacrifices his body, the wear and tear on the body will hurt that player over a large scale of time(which will hurt the team)

I think short term blocking shots improves your chance of winning(basically if you looking at it from a game by game basis) but long term having injuries and players not at 100% will hurt you, especially if you have bigger goals like playing 4 rounds of playoffs

 

[Rogie]

Here's a theory; and I played goal (not pro or semi-pro) but up to junior and then senior hockey for a good 40 years.

I was always yelling at Dmen to get out of the way; block it or get out of the way, but a lot of time, just get out of the way; the puck might be (often) catchable or easy to deflect in the corner. Shots that are from the point or a bit closer in, shots from the top of the circle distance - if a player has time to make a decision to block or get out of the way, that likely means, the goalie has enough time to take care of most shots; ALSO add to this that the goalie can control rebounds and deflect the puck to safety whilst players are just trying to get in the way (and protect themselves at the same time).
Could it be that D-men (or forwards) intent on blocking shots mess up the goalie's chance of stopping some shots - especially shots they just get a small piece of or end up screening the goalie on a failed blocked shot. So, the Kings might work on being more conscious of allowing Quick to see shots more easily, if they can't force or tip a puck firstly. So, teams with high shot blocking rates (albeit the odd seemingly SAVED goal by a shot block) maybe are hindering or interfering with goalies ability to make more saves. Obviously, instances come to mind where in a scramble in very tight, a blocked shot might be the only way to save a goal, but, I can think many instances, where I just feel like - get out of the way completely - stand aside and let me stop it!!!!!

 

[Mathletic]

haven't followed the whole thread but there's an article about shot blocking on nhlnumbers

http://nhlnumbers.com/2013/5/29/lets-talk-about-shot-blocking

 

[Cunneen]

Here's a theory; and I played goal (not pro or semi-pro) but up to junior and then senior hockey for a good 40 years.

I was always yelling at Dmen to get out of the way; block it or get out of the way, but a lot of time, just get out of the way; the puck might be (often) catchable or easy to deflect in the corner. Shots that are from the point or a bit closer in, shots from the top of the circle distance - if a player has time to make a decision to block or get out of the way, that likely means, the goalie has enough time to take care of most shots; ALSO add to this that the goalie can control rebounds and deflect the puck to safety whilst players are just trying to get in the way (and protect themselves at the same time).
Could it be that D-men (or forwards) intent on blocking shots mess up the goalie's chance of stopping some shots - especially shots they just get a small piece of or end up screening the goalie on a failed blocked shot. So, the Kings might work on being more conscious of allowing Quick to see shots more easily, if they can't force or tip a puck firstly. So, teams with high shot blocking rates (albeit the odd seemingly SAVED goal by a shot block) maybe are hindering or interfering with goalies ability to make more saves. Obviously, instances come to mind where in a scramble in very tight, a blocked shot might be the only way to save a goal, but, I can think many instances, where I just feel like - get out of the way completely - stand aside and let me stop it!!!!!

I think your personal experiances as a goalie point to a potential revelation about shot blocking. Check out the link above me form NHL numbers. It suggests (as the quote above me does) is that most blocked shots are low percentage shots that do not need to be blocked. Thus, the screen on your own goaltender that is created by trying to block shots and the odd deflection off your own body towards the goal is potentially worse than the benefits of blocking shots.

Now let me say that this has not been proven statistically. This is a theory that many of us have in the advanced stat community. And unfortunately, since the NHL doesn't to my knowledge track the locations of blocked shots, it would be very tough to figure this out. But it seems to me that there is a difference between blocking a shot from the point and blocking one in the high slot. The one in the high slot is much more likely to go it so theoretically the benefits from attempting to block the shot may outweight the previously outlined risks.

Overall, its an interesting discussion. Shot blocking has for so long been viewed as a positive, but only now are we really looking at the pros and cons of shot blocking from an analytical perspective.

 

[Cunneen]

more blocked shots = greater chance of injury

While it's commendable that somebody sacrifices his body, the wear and tear on the body will hurt that player over a large scale of time(which will hurt the team)

I think short term blocking shots improves your chance of winning(basically if you looking at it from a game by game basis) but long term having injuries and players not at 100% will hurt you, especially if you have bigger goals like playing 4 rounds of playoffs

That is certainly an interesting theory to have. If we had the # of man games lost per season for every team, we could see if any correlation exists between man games lost per season and shot blocking totals.

Your theory seems reasonable, I'd just like to look at whether the data backs up your assertion or not.

If anyone has the team injury totals per season please either post a link or let me know

 

[Cursed Lemon]

Isn't the most significant thing here to determine whether or not those blocked shots are prevented goals?

 

[Bear of Bad News]

Isn't the most significant thing here to determine whether or not those blocked shots are prevented goals?

How do you suggest that we approach that?

 

[boredmale]

That is certainly an interesting theory to have. If we had the # of man games lost per season for every team, we could see if any correlation exists between man games lost per season and shot blocking totals.

Your theory seems reasonable, I'd just like to look at whether the data backs up your assertion or not.

If anyone has the team injury totals per season please either post a link or let me know

I know as an Islanders fan, we generally rate high in average shots blocked per game as well as injuried man games lost the past few seasons(although this year we were relatively injury free). That though is just a 1 case example and I am biased

 

[boredmale]

Here is going off 2011/12 stats

http://www.mangameslost.com/end-of-regular-season-nhl-man-games-lost-april-8-2012/

Montreal 1 439
Columbus 2 409
Calgary 3 389
Minnesota 4 388
Pittsburgh 5 355
NY Islanders 6 351
Florida 7 340
Buffalo 8 328
St. Louis 9 316
Tampa Bay 10 311
Winnipeg 11 281
Vancouver 12 271
Edmonton 13 248
Washington 14 248
New Jersey 15 243
Toronto 16 239
NY Rangers 17 235
Ottawa 18 225
Detroit 19 223
Colorado 20 210
Anaheim 21 200
Carolina 22 199
Phoenix 23 181
Dallas 24 172
Chicago 25 168
Los Angeles 26 168
San Jose 27 148
Nashville 28 143
Boston 29 135
Philadelphia30 0

In terms of where these teams finished in terms of blocked shots

http://www.nhl.com/ice/teamstats.ht...AALL&sort=blockedShots&viewName=realTimeStats

Montreal 3
Columbus 24
Calgary 16
Minnesota 2
Pittsburgh 22
NY Islanders 1
Florida 25
Buffalo 20
St. Louis 17
Tampa Bay 7
Winnipeg 14
Vancouver 27
Edmonton 10
Washington 6
New Jersey 30
Toronto 11
NY Rangers 4
Ottawa 19
Detroit 28
Colorado 18
Anaheim 15
Carolina 9
Phoenix 21
Dallas 8
Chicago 26
Los Angeles 29
San Jose 5
Nashville 12
Boston 23
Philadelphia 13

 

[Barnes]

Isn't the most significant thing here to determine whether or not those blocked shots are prevented goals?

It most certainly is one of the most significant things here...but how could that possibly be determined if it never gets to the point where the event actually happens?

 

[LeBlondeDemon10]

What's interesting is that blocking shots doesn't seem to have much, if any effect on goals against.

You'd think teams with the most blocked shots would have at least like 10% less goals against or something, but I guess what this really shows is that by blocking more shots, a team is also giving up more shots, which in turn results in more goals against. Plus blocking shots often just returns the puck to the player(s) who had control of it before anyways, so they're just going to keep shooting until they get one on.

Obviously there are going to be instances where a blocked shot actually does save a goal, but apparently not enough to make a big impact

As Don Cherry says - get the hell out of the way so your best shot blocker, the goalie, can see the puck.

 

[Patman]

Hmm... so no evidence of linearity (I can't imagine that one line would pass any level of significance test.)

What does the block shot do... ideally the sacrifice of the body in terms of positioning, movement, and ouchies, should, as the case may be, be the better means than other options (basic game theory, etc.).

Now, as a tactic, that's hard to judge and it looks like the plots imply nothing obvious. Of course, this can go oh so many ways. I would bet this would be a hard signal to tease from noise. Hockey is still very much a non-discrete sport and just because you blocked a shot doesn't make it a good choice per se... all a matter of how and where the puck goes next.

I would think this strategy would be somewhat self-regulatory. If one takes it to the extremes the other team would take advantage of the acknowledged hedge in opponent judgement so I'd have to think a reasonable equilibrium would be maintained... so determining the effect on win ratios across a plausible domain may be hard to judge.

 

[Shoalzie]

Just a general observation on shot blocking and goaltending...is a lot of what we see in today's game a product of bigger guys playing this game and those players playing with a lot of extra protection? If you're bigger, you take up more space and if you have more protection, you're more apt to jump in front of a shot than if you had less gear, right?

I think the art of shot blocking is kind of a like what goaltending has become in the "big pad era". It's not as much about reacting to a shot to make a save or block a shot, it's about just taking as much space away for which the puck can travel. Getting in a shooting lane is basically what goaltending is where you just get in between the puck and the goal and if a guy can hit an open spot, then good on them.

As far as the blocked shot argument...if you're generally outshooting or outpossessing a team, doesn't that mean more than just being able to block thje most shots? If you're spending more time blocking shots in your own zone, that's just more time you're spending not producing scoring chances on the other end of the ice. Unless you can score goals on fewer shots...I don't see how a team can rely on shot blocking as a way to win. It's a defensive strategy but it doesn't put pucks in the other net.

I'd like to see where giveaways/takeaways play a part in team success. I think the ability to not giveaway the puck in your own zone or in the neutral zone and conversely, the ability to force turnovers on teams in their end or the neutral zone can lead to success rather than just relying on being able to get in the front of as much shots as you can. Shot blocking has to help in some way but it probably just means less shots your goalie has to actually stop. You can block tons of shots but what if your goalie stinks?

Shot blocks prevents scoring chances but stealing the puck prevents scoring chances and can create quality chances on the other end via odd man rushes or transition chances. Shot blocks are useful if you can retrieve those loose pucks and prevent yourself from having to block multiple shots or to keep you from having to ice the puck to get out of danger.

 

[I am Lorde]

My thought: a shot blocked means that you allowed the team to shoot the puck in the first place. The teams who are blocking a lot of shots are allowing a lot of shot attempts. So while there is a negative correlation between blocked shots and winning, this doesn't necessarily mean that you're better off to let them shoot it on net. Plan a should be not to even have to block the shot.

Hypothetical situation A: my team is drunk and my opponents attempt 500 shots against us. We block 400 of them (that's a lot of blocked shots). The other 100 shots all hit the net. We probably lose that game 10-0.
Hypothetical situation B: my team is drunk again and facing another 500 shot attempts. This time we say f-that and get out of the way of every shot. Now the goal light is broken and both of my goalies are in comas.

Maybe a more valuable stat would be shots blocked per shots against. If there is a correlation between that rate and winning then we know whether to block a shot or get the hell out of the way.

 

[NewLife]

The best thing about block shots isn't always to actually get the shot blocked, it's you take a away the best shooting lane if you do if properly and often force the shooter to strike it wide of the net. However it often create chaos in your own zone witch is the down side beside the obviously risk of screen your own goalie but somehow goalies today are extremely great at tracking pucks in traffic.

I believe your goal against is in favor of the system but your goals for also goes down since your break out often aren't there, at least for the Rangers.

 

[hatterson]

Here's a few ideas I have to drive analysis. I'm not sure if I'll have a chance to look at the numbers, but I thought I'd throw it on here for others to digest and comment on.

First we'll start with the meta analysis. Two statistically average teams play against each other. On average they each score 50% of the goals that occur (GF% and GA% = 50). Suddenly team A decides "hey maybe if I stood in front of Team Bs shots they'd score less" and team B copies them, but isn't as good. Team A is able to block 30% of team Bs shots, but team B only blocks 10% of team As

Now, logic would tell us that **if all else is equal** Team A should now be scoring a higher percentage of the goals. However the numbers, as provided here by Cunneen, shows us that they don't, therefore either we have faulty data (it doesn't appear we do) or our assumption ("all else is equal") is incorrect. Since I trust the data, lets try and delve into what might not be correct.

I look at it this way. Lets look at two stats I'll call the Corsi Shooting Percentage (I have no idea if this stat has a real name, I didn't see it anywhere) which is simply Goals Scored / Corsi Events for an individual player and the Fenwick Shooting Percentage (ditto on the name) If I have 5 shots on goal, 3 shots of mine blocked and fire another 2 wide, and out of that net 1 goal I have a CSh of 10% and a FSh of 12.5%. Goals scored would simply be CSh * corsi or FSh * fenwick

Now from our setup, both teams are statistically average meaning they have the same number of corsi and fenwick events occurring. In this case

CSh(a) * corsi(a) = CSh(b) * corsi(b) = X
and
FSh(a) * fenwick(a) = FSh(b) * fenwick(b) = X

Where X is goals scored by each team. This also means that for a given team

CSh * corsi = FSh * fenwick

In our initial setup there are no blocked shots so corsi = fenwick and CSh = FSh

But now we look at block percentages. Lets say team A is blocking 30% of shots against and team B is blocking 10% against. Now fenwick(b) = .7 * corsi(b) and fenwick(a) = .9 * corsi(a). But here's where the interesting bit comes in. According to the numbers Cunneen compiled the original equations still hold true.

CSh(a) * corsi(a) = CSh(b) * corsi(b) = X
and
FSh(a) * fenwick(a) = FSh(b) * fenwick(b) = X

Now that we have blocks however our substitutions can become fun by substituting fenwick(a) and fenwick(b) for their relative corsi.

FSh(a) * .9 * corsi(a) = FSh(b) * .7 * corsi(b) = X
or simplified
FSh(a) * corsi(a) = .777 FSh(b) * corsi(b)

In order for that to happen either corsi(b) must be lower than corsi(a) or FSh(b) must be lower than FSh(a), or both.

In plain terms it seems to me that it means either.
1.) Blocked shot percentage has an inverse correlation with corsi against. The higher percentage of shots I block, the more get thrown towards me.
or
2.) Blocked shot percentage has an inverse correlation with FSh against. The higher percentage of shots I block, the higher percentage of goals an opponent scores on a given number of fenwick events
Or
3.) Both


From an anecdotal standpoint I can defend these. If I'm blocking shots I'm also in the goalie's way, so he's less likely to see the puck and more likely to let it in (so says common sense). Similarly, if I'm blocking shots, I'm more often than not giving the pick back to the opponent so he can simply take another one (again, according to common sense). However, I have no statistical proof of either of these.

Does that make sense to anyone? Did I screw up my analysis somewhere?

 

[hatterson]

<snip>

In plain terms it seems to me that it means either.
1.) Blocked shot percentage has an inverse correlation with corsi against. The higher percentage of shots I block, the more get thrown towards me.
or

As I thought a little more about this, I guess it doesn't have to be corsi against. It could be net corsi. Perhaps the act of blocking shots also mitigates your ability to direct shots at the opponents net.

I'd be interested to see what the following relationships revealed.

Blocked shot percentage for vs corsi against - Does blocking shots have a relationship with total shots directed towards your net?
Blocked shot percentage for vs corsi for - Does blocking shots have a relationship with total shots you direct towards your opponents net?
Blocked shot percentage for vs corsi total - Does blocking shots have a relationship with total shots directed on net in a game?
Blocked shot percentage for vs corsi for percentage - Does blocking shots have a relationship with the percentage of total shots directed on net that are yours?
Blocked shot percentage for vs corsi shooting percentage against - Does blocking shots have a relationship with the percentage of directed shots that result in goals?
Blocked shot percentage for vs fenwick shoot percentage against - Does blocking shots have a relationship with the percentage of fenwick events that result in goals?
Blocked shot percentage for vs fenwick for - Does blocking shots have a relationship with the number of shots that you get past blockers?
Blocked shot percentage for vs fenwick against - Does blocking shots have a relationship with the number of shots that get past your blockers?
Blocked shot percentage for vs fenwick total - Does blocking shots have a relationship with the total number of shots that get past blockers in a game?
Blocked shot percentage for vs fenwick for percentage - Does blocking shots have a relationship with the percentage of shots that get past blockers that are yours?

 

[Cunneen]

As I thought a little more about this, I guess it doesn't have to be corsi against. It could be net corsi. Perhaps the act of blocking shots also mitigates your ability to direct shots at the opponents net.

I'd be interested to see what the following relationships revealed.

Blocked shot percentage for vs corsi against - Does blocking shots have a relationship with total shots directed towards your net?
Blocked shot percentage for vs corsi for - Does blocking shots have a relationship with total shots you direct towards your opponents net?
Blocked shot percentage for vs corsi total - Does blocking shots have a relationship with total shots directed on net in a game?
Blocked shot percentage for vs corsi for percentage - Does blocking shots have a relationship with the percentage of total shots directed on net that are yours?
Blocked shot percentage for vs corsi shooting percentage against - Does blocking shots have a relationship with the percentage of directed shots that result in goals?
Blocked shot percentage for vs fenwick shoot percentage against - Does blocking shots have a relationship with the percentage of fenwick events that result in goals?
Blocked shot percentage for vs fenwick for - Does blocking shots have a relationship with the number of shots that you get past blockers?
Blocked shot percentage for vs fenwick against - Does blocking shots have a relationship with the number of shots that get past your blockers?
Blocked shot percentage for vs fenwick total - Does blocking shots have a relationship with the total number of shots that get past blockers in a game?
Blocked shot percentage for vs fenwick for percentage - Does blocking shots have a relationship with the percentage of shots that get past blockers that are yours?

I can take a look at these relationships for you

 

[Kershaw]

Nope. Preventing shots against is a more efficient way to help win games.

 

[Cunneen]

Nope. Preventing shots against is a more efficient way to help win games.

well obviously, but these two concepts aren't mutually exclusive

 

[Cunneen]

As I thought a little more about this, I guess it doesn't have to be corsi against. It could be net corsi. Perhaps the act of blocking shots also mitigates your ability to direct shots at the opponents net.

I'd be interested to see what the following relationships revealed.

Blocked shot percentage for vs corsi against - Does blocking shots have a relationship with total shots directed towards your net?
Blocked shot percentage for vs corsi for - Does blocking shots have a relationship with total shots you direct towards your opponents net?
Blocked shot percentage for vs corsi total - Does blocking shots have a relationship with total shots directed on net in a game?
Blocked shot percentage for vs corsi for percentage - Does blocking shots have a relationship with the percentage of total shots directed on net that are yours?
Blocked shot percentage for vs corsi shooting percentage against - Does blocking shots have a relationship with the percentage of directed shots that result in goals?
Blocked shot percentage for vs fenwick shoot percentage against - Does blocking shots have a relationship with the percentage of fenwick events that result in goals?
Blocked shot percentage for vs fenwick for - Does blocking shots have a relationship with the number of shots that you get past blockers?
Blocked shot percentage for vs fenwick against - Does blocking shots have a relationship with the number of shots that get past your blockers?
Blocked shot percentage for vs fenwick total - Does blocking shots have a relationship with the total number of shots that get past blockers in a game?
Blocked shot percentage for vs fenwick for percentage - Does blocking shots have a relationship with the percentage of shots that get past blockers that are yours?

Alright, it took me a while, but I got the relationships above. I will Post the R^2 value of each relationship. The data if from 2007-2008 season to the 2011-2012 season. All data is even strength

All data besides the % stats are rate stats per 60 minutes. So for the first one (Corsi against), it is corsi against per 60 mintutes of even strength play


Blocked shot percentage for vs corsi against : R^2 = .20648


Blocked shot percentage for vs corsi for : R^2 = .02044

mostly an irrelevant comparison since Blocked Shot percentage for (BSPF) is a defensive stat while Corsi for is an offensive stat

Blocked shot percentage for vs corsi total 60 : R^2 = .19203

Blocked shot percentage for vs corsi for percentage : R^2 = .05535

Blocked shot percentage for vs corsi shooting percentage against : R^2 =.035

Blocked shot percentage for vs fenwick shoot percentage against : R^2 = .01382

Blocked shot percentage for vs fenwick for: R^2 = .000036


mostly an irrelevant comparison since Blocked Shot percentage for (BSPF) is a defensive stat while Fenwick for is an offensive stat

Blocked shot percentage for vs fenwick against: R^2 = .01186

Blocked shot percentage for vs fenwick total : R^2 =.00739

Blocked shot percentage for vs fenwick for percentage : R^2 = .0058

 

[hatterson]

Blocked shot percentage for vs corsi for : R^2 = .02044
mostly an irrelevant comparison since Blocked Shot percentage for (BSPF) is a defensive stat while Corsi for is an offensive stat

Blocked shot percentage for vs fenwick for: R^2 = .000036
mostly an irrelevant comparison since Blocked Shot percentage for (BSPF) is a defensive stat while Fenwick for is an offensive stat

Yep, I was mainly looking at this from the standpoint of answering the question, "Does the act of blocking a shot make it more or less likely (or neither) that you are able to get a shot at the opponents goal?"

The answer clearly seems to be 'neither'

Blocked shot percentage for vs corsi against : R^2 = .20648
Blocked shot percentage for vs corsi total 60 : R^2 = .19203
Blocked shot percentage for vs corsi for percentage : R^2 = .05535
Blocked shot percentage for vs corsi shooting percentage against : R^2 =.035

It appears that the percentage of shots blocked has a decent relationship (.2 isn't a great r^2 value, but it's decent for this stuff) with the number of shots you face.

Blocked shot percentage for vs fenwick shoot percentage against : R^2 = .01382
Blocked shot percentage for vs fenwick against: R^2 = .01186
Blocked shot percentage for vs fenwick total : R^2 =.00739
Blocked shot percentage for vs fenwick for percentage : R^2 = .0058

To me these results are interesting as well. What this is basically saying is that blocking an increasing percentage of shots does not mean that fewer shots are getting through to your goal per 60 minutes.

Statistically, it appears teams who have blocked a larger percentage of shots have still had roughly the same number of shots either hit their goalie or miss, and the percentage of those that go in doesn't change.

 

[Cunneen]

It appears that the percentage of shots blocked has a decent relationship (.2 isn't a great r^2 value, but it's decent for this stuff) with the number of shots you face.

So now the question is what does this tell us. At first, I would have thought that this relationship means that teams get better at blocking shots when they face more shot attempts. If this were true, then shot blocking at a higher rate wouldn't be that valuable since it also carries with it giving up more shots attempts per 60 minutes. But given that there was no relationship between blocked shot percentage for and the Fenwick relationships, this tells me that teams give up the same amount of missed shots and shots on goal regardless of their shot blocking ability. Which means that teams don't improve at shot blocking as they give up more shot attempts.

 

[Cunneen]

So now the question is what does this tell us. At first, I would have thought that this relationship means that teams get better at blocking shots when they face more shot attempts. If this were true, then shot blocking at a higher rate wouldn't be that valuable since it also carries with it giving up more shots attempts per 60 minutes. But given that there was no relationship between blocked shot percentage for and the Fenwick relationships, this tells me that teams give up the same amount of missed shots and shots on goal regardless of their shot blocking ability. Which means that teams don't improve at shot blocking as they give up more shot attempts.

So while shot blocking at a higher rate isn't a bad thing, it also doesn't seem to be a good thing. Given that teams that block a higher percentage of shots don't give up less shots and less missed shots, shot blocking at a higher rate isn't actually accomplishing anything.


So say you have two teams (Team A and Team B). Team A and B are identical except for the fact that Team A blocks shots at a better percentage then Team B. According to the relationships I found, there should be not much difference between the Fenwick of the two teams. however, the Corsi of team A may be a little higher. Which means that Team A may be giving up a few extra shot attempts, but almost all those shot attempts are getting blocked.

So whether you block shots at a rate of 25% or 30%, your Fenwick seems to be unaffected. Same goes with Shots against (R^2 was almost 0). I think this is the big question. Why? Why does it seem that shot blocking at a higher rate has no affect on how many shots either miss the net or hit the goalie?