Dec 092011
 

Gabe Desjardins of Arctic Ice Hockey asks the question about whether a player can influence his teammates shooting percentage.  To answer this question he took a look at the Pittsburgh Penguins shooting percentages with and without Mario Lemieux.  The conclusion:

I’d posit that Lemieux’s playmaking contribution is about as large as we’re going to consistently find – something on the order of 7-8% – and we can use it to bound the impact that a player can truly have on the quality of his teammates’ scoring chances.

Since I have the numbers handy I figured I’d take a look at some more recent examples but instead of looking at straight shooting percentage I looked at corsi shooting percentage (since I had corsi data more available).  Corsi shooting percentage is simply goals for divided by corsi for.  I’d consider Joe Thornton one of the premiere playmaking centers in the league today so let’s take a look at how some players performed while playing with, and without, him.

CSH% With Thornton CSH% Without Boost
Marleau 4.93% 3.88% 27.02%
Setogutchi 5.09% 3.80% 33.82%
Heatley 5.59% 4.32% 29.50%

I included the past 4 years with Marleau, 3 years with Setogutchi and 2 years with Heatley.  That would indicate Thornton has an approximately 30% boost in corsi shooting percentage to his teammates.  Certainly far more than the 8% Gabe predicted as the upper bound.

Now, let’s take a look at another great player, Sidney Crosby.

CSH% With CSH% Without Boost
Malkin 7.30% 5.15% 41.89%
Dupuis 5.73% 4.06% 40.95%
Fleury 5.75% 4.22% 36.15%

All players are using 4 years of data.  I included Fleury in the list because it provides a good proxy of the Penguins shooting percentages when Crosby is on the ice vs when he is not.  This would seem to indicate that Crosby is worth a nearly 40% boost in his teams shooting percentage.  That’s significantly more than even Thornton and a massive amount more than Gabe’s estimated upper bound.  Maybe we should revise the upper bound to be 40%, not 8%.

For interest sake, here how much Crosby influenced his teammates corsi rates.

Boost in CF20
Malkin 21.15%
Dupuis 18.15%
Fleury 15.59%

While a ~20% boost is significant, it is at best only half the boost he provided to corsi shooting percentage.  Driving shooting percentage is a more significant reason why Crosby is so good offensively than driving corsi events.

 

Update:  Eric over at Broad St. Hockey has an interesting post looking at individual shooting percentages as opposed to on-ice shooting percentages as I did above.  Four of the players he looked at are H. Sedin, Crosby, Thornton and Datsyuk and for each he looked at a number of teammates with at least 30 shots with and without.  Taking it a step further I think it is necessary to average across players to get a better idea of what is happening.  If you do that, this is what you get:

With Without Boost
Sedin 11.19% 6.81% 64.28%
Crosby 9.14% 7.55% 21.17%
Thornton 9.69% 7.27% 33.19%
Datsyuk 9.36% 6.98% 34.09%

Wow, that might make Sedin the best playmaker in the league, by a significant margin.  Crosby doesn’t look quite as good as my “on-ice” analysis but that is because much of the reason why Crosby improves his linemates on-ice shooting percentage is because he is such a great shooter himself.

The point still stands, without considering shooting percentages we aren’t getting anywhere close to having a complete analysis of a players impact on the game.

 

Sep 152011
 

Over on Pension Plan Puppets there was a brief discussion of some of the top defensive defensemen and I suggested that Mike Weaver has to be considered among the top few defenders in the NHL.  The response was generally along the lines of ‘Mike who?’ and then followed with “he only looks good because he plays in front of Vokoun who may be the best goalie in the NHL.”  My thoughts on Vokoun being over rated aside, the numbers really do support Weaver as being a premiere level defensive defenseman.  Let’s look at some Mike Weaver numbers.

Over the past 4 seasons Mike Weaver played one season in Vancouver, 2 seasons in St. Louis and last season he was in Florida.  During that time there have been 173 defensemen who have played >1500 5v5 close (within 1 goal in first or second period or tied in third period) minutes and of those 173 defensemen Weaver ranks fourth in on ice goals against per 20 minutes of ice time.  He only trails Bryce Salvador, Sean O’Donnell and Paul Martin (3 other under rated defenders IMO).  Ranking 4th is a pretty good argument for why he is a great defender.  So what about the typical excuses for why he might rank so highly?

1.  Goalies make him look good.  Not really.  In the past 4 years he has played 2455:08 minutes of 5v5close ice time, 798:24 (32.5%) in front of Chris Mason, 587:45 (23.9%) in front of Vokoun, 390:58 (15.9%) in front of Luongo, 297:47 (12.1%) in front of Clemmensen, 185:04 (7.5%) in front of Conklin and some time in front of a few other lesser goalies.  At best you can argue he has played 45% of his time behind premiere level goalies (Vokoun and Luongo) with the remaining 55% behind second tier starters (Mason) or third tier starters and backups (Conklin, Clemmensen, etc).  In his year in Vancouver, the Canucks ranked a solid 7th in team goals against average but his 2 years in St. Louis the Blues ranked 12th and 11th and last year the Panthers ranked 14th so while he hasn’t played on any bad defensive teams he hasn’t played on any elite defensive teams either.  It’s difficult to make the case he has had an unusually significant benefit from playing in front of elite goalies or on elite defensive teams.

2. He Plays Easy Minutes.  Not really.  Over the past 4 seasons he ranks 45th of 173 defensemen with 34.1% of his face offs in the defensive zone and last season he started 36.9% of the time in the defensive zone or 21st highest of 157 defensemen with 500 5v5close minutes.  Over the past 4 seasons his opposition goals for per 20 minutes ranks 31st of 173 defensemen so he is seemingly playing against quality offensive forwards.  Last season the forwards he played most against were Ovechkin, Backstrom, Knuble, St. Louis, and Stamkos so yeah, that’s pretty good competition.  Over the past 2 seasons only Chris Phillips and Jay Bouwmeester have played more time on the 4v5 penalty kill than Weaver.  He is trusted playing tough minutes against top competition so the easy minutes argument is not valid.

While we are at it, Mike Weaver is another example why I do not like corsi/fenwick stats.  While Weaver has the 4th best on-ice 5v5close goals against per 20 minutes, he ranks a far less impressive (though still a little above average) 47th in fenwick against per 20 minutes.  The main reason why Weaver is so good defensively is he suppresses shot quality really well.  He ranks 3rd in shooting percentage against (or save percentage) while he is on the ice and he has been consistently above average over the past 4 seasons (6th of 176 in 2007-08, 63rd of 147 in 2008-09, 13th of 154 in 2009-10 and 22nd of 157 in 2010-11).  Three of the past 4 seasons he has been a top 25 defenseman in terms of shooting percentage against and the fourth and worst season he was still in the top half.  Sorry, but there is no ‘regressing to the mean’ there.

Mike Weaver is a premiere, and vastly under rated and under paid ($900,000), defensive defenseman.

 

Jul 162011
 

Last night after news came out that Brendan Morrison had re-signed with the Calgary Flames, Kent Wilson tweeted the following:

Morrison back in Calgary. Check out his corsi tied rating fellow stats nerds: http://bit.ly/q1ywUj

The link is to the Calgary Flames 5v5 game tied corsi ratings which show Morrison had a 0.452 corsi rating (Corsi For %) which was dead last on the Flames.  The problem with jumping to the conclusion that Morrison is bad is two fold:

1.  Corsi generally speaking isn’t good at evaluating players.

2.  One year of 5v5 game tied data is not enough to evaluate players, even with corsi.

Lets take a look at Brendan Morrison over the past 4 years and I’ll show you exactly what I mean.  First lets look just at 5v5 any game score situations.

Season(s) CorF% GF%
2010-11 0.484 0.562
2009-10 0.514 0.627
2008-09 0.498 0.569
2007-08 0.430 0.500
2007-11 (4yr) 0.491 0.577

In each and every year the goals for percentage is significantly higher than his corsi for percentage.  His corsi ratings make Morrison look mediocre at best but his goal ratings make him appear to be quite good.  This isn’t a fluke.  It is occurring systematically, every single season, over 4 seasons in which Morrison played for 5 different teams (Vancouver, Anaheim, Dallas, Washington, Calgary).

Now what about 5v5 game tied situations.  Morrison’s 4 year game tied corsi for percentage is 0.482, his 4 year game tied goal for percentage is 0.592 (which ranks 28th of  217 among forwards with at least 1000 5v5 game tied minutes over the past 4 seasons).

Personally, I’d rather have good goal ratings than good corsi ratings.  Morrison is a good signing by the Flames.