Wednesday, April 28, 2010

Winning By Getting Outshot

In 2009-10, including the playoffs, the Montreal Canadiens are 9-1-0 when allowing 46 or more shots against. The same team is just 3-14-2 when allowing between 26 and 30 shots against.

That doesn't seem to make a lot of sense, especially given that the team's goal support numbers are not that far apart (2.86 goals per 60 minutes for 46+ SA games, 2.53 goals per 60 minutes for 26-30 SA games). The difference looks to be because the Habs (and their opponents) tend to adjust their play to the score. When Montreal beats better teams, especially in games where they take the lead early, they usually allow a lot of shots against. When Montreal loses, especially in games where they fall behind early, they tend to allow an average level of shots against.

Here are the period-by-period shooting percentage, save percentage and shots for/shots against numbers for Montreal in both 26-30 and 46+ shot games this season:

26-30 Shots Against:
First period: 6.0%, .881, 215 SF, 185 SA
Second period: 8.5%, .889, 216 SF, 201 SA
Third period: 4.8%, .924, 210 SF, 179 SA

46+ Shots Against:
First period: 18.6%, .957, 70 SF, 163 SA
Second period: 8.2%, .975, 85 SF, 158 SA
Third period: 7.4%, .947, 81 SF, 150 SA

I know En Attendant Les Nordiques has scoring chances for Montreal this season. I really wish my French was better because what I do understand of his analysis is always very interesting. I'd like to see how much the Habs' scoring chances are affected by the game score, and just how much the chance-to-shot ratio varies depending on whether they are leading or trailing. The percentages above make it look like the leading team, either Montreal or their opponent, managed with some success to reduce scoring chances for both teams in the third period.

His numbers from game 6, though, suggest that Montreal was not able to reduce shot quality very much in the late going. In the last two periods Washington outshot Montreal 36-12 and outchanced them 25-8. Jaroslav Halak had to make a ton of tough saves to keep his team in front. It should be noted that the Caps are a great team that would probably outplay Montreal anyway, which it makes it tough to tell how much of that chance differential was the impact of their tactics and how much of it was because of a difference in ability.

If Montreal gets up early tonight we can expect an avalanche of chances from the Caps, and they're going to need Halak to hold the fort again. If Washington goes out in front, they'll probably play a bit more defensively and be a bit more selective with their shots. As a result, if Halak makes 45+ saves tonight it will most likely be in a Habs win or overtime loss. If Washington's final shot total ends up in the 26-30 range, that's probably not going to be good news for Montreal.

13 comments:

R O said...

If Montreal gets up early tonight we can expect an avalanche of chances from the Caps, and they're going to need Halak to hold the fort again. If Washington goes out in front, they'll probably play a bit more defensively and be a bit more selective with their shots. As a result, if Halak makes 45+ saves tonight it will most likely be in a Habs win or overtime loss. If Washington's final shot total ends up in the 26-30 range, that's probably not going to be good news for Montreal.

Although I think you and I would both agree, that WSH's game plan going in won't be "reduce the number of shots we take".

Reality will just (likely) bear out that Washington won't rain chances down in insane quantities if they score two or three quickly.

Olivier said...

Oh hey, glad to see the scoring chances are of any use to you!

I'd add a few things:

- A big slice of last game's chances for Washington came on the PP. That's what happens when you don't allow a single goal but keep getting in the box against these guys.

- At ES, MTL actually had 10 chances on 18 shot attempts in the first against 6 chances over 25 attempts for Washington. For the last two periods, we had 5/19 for MTL and 12/38 Washington.

- That whole chances/score situation thing is pretty interesting. Maybe someone will beat me to it, but I certainly intend to do something about that in the next few weeks. At least run some numbers.

Anonymous said...

Make that 10-0-1!

Anonymous said...

TCG called it.

Taylor said...

What a horrible game. MTL collapsed around their net and just let WSH fire away. WSH had very few really good scoring chances. They just had to hope one of their decent scoring chances would go in. Terrible to watch and terrible for the NHL.

Jonathan said...

Sitting on a 1-0 lead seems to be an irrationally risk-averse strategy for Montreal. (or in conventional wisdom speak, they were playing not to lose, the prevent defense prevents you from winning, etc.)

It seems like the strategy of collapsing around the net is going to cause more danger to your goalie than it will prevent. I am no scout so it's really hard for me to just eyeball the situation by watching the game, but it sure did seem to me like Washington had a barrage of chances and Montreal was quite fortunate to hold Washington to three or fewer, let alone a single goal.

The guy at advancednflstats.com (as well as other stat-heads) has often argued that NFL coaches don't take nearly as many chances as they should, stating that they kick too often on fourth down. I mean, waaaayy too often. I wonder if teams can be criticized similarly when they "play to the score." Is it a good idea to collapse into a defensive formation, or should the teams keep playing as if it were 0-0? At what point should teams start playing to the score? I don't know what the answer is, but I have a very strong feeling that it is sometimes later than 0:05 of the second period for a one-goal lead.

MathMan said...

Something to consider when considering outshooting on a single-game timeframe: out of the NHL's 30 teams, 19 had a better record when outshot than they had when outshooting this year.

Bruce said...

46+ Shots Against:
First period: 18.6%, .957, 70 SF, 163 SA
Second period: 8.2%, .975, 85 SF, 158 SA
Third period: 7.4%, .947, 81 SF, 150 SA


The interesting thing here is that in this (small) data set, Montreal actually got outshot even worse in the first period than the second or third. I would have guessed that in games where they jumped out front they would do relatively OK on the shot clock until that point, then get bombarded after that. But this suggests they were under the gun, and scoring against the flow of play, right from the outset.

Taylor said...

My impression while watching the game was that while Washington was getting a lot of shots, they really weren't getting any (except for the slot feed to Chimera which he couldn't handle cleanly) really good chances. Lots of 'ok, that kind of shot goes in once in a while' chances, but only that one chance that I really thought had a good chance of being a goal. I just never had the sense that they were going to score. I was actually surprised when they finally did. Maybe I was being pessimistic because I wanted to see the best team advance (I don't root for either team) but it just looked like the neutral-zone trap ala NJ of the '90s all over again.

R O said...

My impression while watching the game was that while Washington was getting a lot of shots, they really weren't getting any (except for the slot feed to Chimera which he couldn't handle cleanly) really good chances

Olivier counted 24 WSH scoring chances at EV. I didn't see them have that much of a problem penetrating the scoring area. Maybe you just think they had trouble because they spent all the freaking time in the offensive zone.

Reference: http://enattendantlesnordiques.blogspot.com/

The Contrarian Goaltender said...

What's the average number of scoring chances allowed per game? I'd guess 24 chances against wouldn't be all that high of a number for a team like Montreal. It's pretty much in line with the rest of the games against Washington, with the exception of game 6. So the Habs must have been doing something right on defence considering they spent most of the game trying to hold a lead against the best offensive team in hockey. Even in game 6 most of the Caps' scoring chances came on the power play. I agree that many overstate the shot quality impact, but I think there is at least something there when a team tries to hold a lead by crowding the front of their own net.

In the second period in particular it looked to me like Montreal succeeded in shutting down the game for the most part, Olivier has Washington at just 2 chances at EV in that period, even though Montreal spent the whole time in the lead. Washington definitely had chances in the third though.

nightfly said...

I can't find it for some reason but I know I've been reading more than a little about shot totals and sv%, and the prevailing evidence is that it's the high sv% that drives shot totals up, not the other way around. This makes sense, as it's another way of expressing score effects - a team with an early lead doesn't need to press and thus the losing goalie will often not have that many shots against.

Kent W. said...

What's the average number of scoring chances allowed per game?

When I was counting for the Flames this year, it was around 35 for both teams combined. And from what we've seen so far, teams tend to score on roughly 1 out of every 5 scoring chances. So a 24 scoring chance game from one team is fairly high event (expected goals = 4 to 5). It was exceedingly rare for the Flames to break the 20 chance mark on any given evening.

Of course, shots from the periphery or the point are worth more than "0" as well since probably about 5% of those pucks find their way in during the season too.

The Habs did what any team under siege do - they collapsed and prayed. Luckily, the hockey gods answered their prayers.