Mar 152011
 

I thought this debate had been fully hashed out already but apparently some people still don’t believe that the game score has an impact on shooting percentage (and shot quality).  The following table shows the shooting percentages by game score over the past 3 seasons (2007-08 to 2009-10) during even strength situations where neither goalie is pulled for any reason (including delayed penalty situations).

Situation Shots Goals SH% Prob<= Prob>
Down2+ 23650 1852 7.83 0.3794 0.6206
Down1 30447 2356 7.74 0.1696 0.8304
Tied 60753 4427 7.29 0.0000 1.0000
Up1 26842 2288 8.52 0.9999 0.0001
Up2+ 19351 1779 9.19 1.0000 0.0000
Overall 161043 12702 7.89 0.5024 0.4976

The Situation, Shots, Goals, and SH% columns are self explanatory.  As you can see, shooting percentage is at its lowest in game tied situations, increases slightly for teams that are trailing and increases significantly for teams that are leading.

The second last column titled Prob<= show the probability (according to a binomial distribution) that that number of goals or fewer would be scored on that number of shots if the expected shooting percentage was 7.89%, the same as the overall 5v5 shooting percentage.  The last column titled Prob> is simply 1-Prob<= and shows the probability of getting more than that number of goals on that number of shots.  So, in down 2+ goal situations, there is a 37.94% chance of their being 1852 or fewer goals scored on 23650 shots which indicates that the down2+ shooting percentage isn’t different from the 5v5 mean at any reasonable confidence level.  The same conclusion can be drawn about down1 situations.  But, the shooting percentages in game tied, up1 and up2+ situations are statistically different at an extremely high confidence level.  Essentially there is zero chance that game tied, up1, or up2+ situations have the same natural shooting percentages as game overall 5v5 situations.  In no way can luck be the sole reason for these differences.

So, does this conclusively tell us that shot quality exists and varies according to game score?  It probably does, but I can’t say it is conclusive as it could mean that teams that trail a lot have bad goaltending (the reason they are trailing) and this results in the team leading having an inflated shooting percentage.  So, what if we looked at shots against a particular team.  Let’s say, for example, against the NY Rangers.  Here is what that looks like.

Situation Shots Goals SH% Prob<= Prob>
Overall 5159 386 7.48 0.5135 0.4865
Up1 843 73 8.66 0.9116 0.0884
Up2+ 485 46 9.48 0.9571 0.0429
Leading 1328 119 8.96 0.9800 0.0200
Tied 2004 138 6.89 0.1658 0.8342

I chose the Rangers because they use predominantly one goalie and that goalie is generally speaking a quality goalie.  As you can see, the confidence levels aren’t quite as strong as league wide mostly because of the smaller sample size but if we combine the up1 and up2+ categories we can say that shot quality against the Rangers when the opposing team is leading is statistically different than shooting percentage against the Rangers overall.

If you are interested in seeing what happens with a team that has had chronically bad goaltending, here is the same table for the Maple Leafs.  We see the same sort of things.

Situation Shots Goals SH% Prob<= Prob>
Overall 5309 491 9.25 0.5120 0.4880
Up1 938 94 10.02 0.8098 0.1902
Up2+ 906 100 11.04 0.9698 0.0302
Leading 1844 194 10.52 0.9712 0.0288
Tied 1985 149 7.51 0.0034 0.9966

So what have we learned.

  1. Shooting percentages vary according to game score.
  2. Those shooting percentage differences can’t be attributed to luck.
  3. Those shooting percentage differences can’t be attributed to goaltending.

That means, it must be the quality of the shots that varies across game scores.  In short, we can conclude that when teams get down in a game they open up and take more chances offensively which in turn gives up higher quality shots against which makes perfect sense to me.

When we combine this with my previous post on the Washington Capitals shooting percentage last season, it is probably safe to assume that shot quality exists and we can’t safely assume that all shots can be treated equal in all situations.

Carcillo/Upshall/Antropov

 NHL  Comments Off
Mar 042009
 

The Flyers have acquired toughness in Dan Carcillo from the Phoenix Coyotes for Scottie Upshall and a second round pick. I think the Coyotes did well in this trade with Upshall and a second round pick but the Flyers do well as well by adding a high energy physical player for a guy, Upshall, who really was lost behind all of the other Flyer forwards.

Also, the Leafs have traded Antopov to NY Rangers for a second round pick plus another conditional pick. Brian Burke wanted a first round pick but he had to settle for a second round pick, which could easily be a mid-second round pick. The conditional pick is probably dependent on whether the Flyers make the playoffs or not.

Aug 172008
 

1 Montreal Canadiens
2 Pittsburgh Penguins
3 Washington Capitals
4 Philadelphia Flyers
5 Ottawa Senators
6 NY Rangers
7 New Jersey Devils
8 Carolina Hurricanes
9 Tampa Bay Lightning
10 Boston Bruins
11 Buffalo Sabres
12 Florida Panthers
13 Atlanta Thrashers
14 Toronto Maple Leafs
15 NY Islanders

Again, I’m going to have to disagree with THN over this. If the Pens had managed to keep Ryan Malone and/or Marian Hossa I’d be inclined to agree that they would finish atop their division, but they won’t. When you potentially have Miroslav Satan as your top scoring winger you’re not going to go anywhere fast. The rest of the team remains largely the same.

I have a hard time believing the Sens will finish ahead of the Rangers and Devils. Despite the fact that Wade Redden‘s game is in decline, losing him will hurt because they didn’t replace him. The Sens are still looking for ways to fill out the rest of their roster, but like so many other teams in the East, goaltending is their primary concern. If Martin Gerber doesn’t hold up, they’re slightly above average at best by virtue of their incredible top line.

The Bruins are going to make some noise this year, especially with a completely healed Patrice Bergeron. Michael Ryder will head into camp as the favourite to land the first line right winger slot, and considering the success Claude Julien had with Ryder, along with an elite playmaking centre in Marc Savard, he could be a very nice surprise. Once again, however, they head into training camp with a 1A-1B tandem of fan favourite Tim Thomas and the disgruntled Manny Fernandez.

The East is much more clear cut than the West because so many teams have holes. The Habs, arguably the best team in the East, also has a shaky goaltending situation considering how Carey Price fell apart last year. These goaltending problems also plague at least 3 of the playoff teams listed. It’ll be interesting to see how this season plays out – a lot of teams have areas to improve, and considering the mass exodus of players from the East heading West, this year could be rather different.