Jul 232014
 

Tyler Dellow has an interesting post on differences between the Kings and Leafs offensive production. He comes at the problem from a slightly different angle than I have explored in my rush shot series so definitely go give it a read. These two paragraphs discuss a theory of Dellow’s that is interesting.

That’s the sort of thing that can affect a team’s shooting percentage. To take it to an extreme, teams shot 6.2% in the ten seconds after an OZ faceoff win this year; the league average shooting percentage at 5v5 is more like 8%. Of course, when you win an offensive zone draw, you start with the puck but the other team has five guys back and in front of you.

I wonder whether there isn’t something like that going on here that explains LA’s persistent struggles with shooting percentage (as well as those of New Jersey, another team that piles up Corsi but can’t score – solving this problem is one of the burning questions in hockey analytics at the moment). It’s a theory, but one that seems to fit with what Eric’s suggested about how LA generates the bulk of their extra shots. It’s hard for me to explain the Leafs scoring so many more goals in the first 11 seconds after a puck has been carried in, particularly given that I suspect that LA, by virtue of their possession edge, probably enjoyed many more carries into the offensive zone overall.

Earlier today I posted some team rush statistics for the past 7 and past 3 seasons. Let’s look in a little more detail how the Leafs, Kings and Devils performed over the past 3 seasons.

Team RushGF RushSF OtherGF OtherSF RushSh% OtherSh% Rush%
New Jersey 45 540 103 1675 8.33% 6.15% 24.4%
Toronto 66 523 128 1675 12.62% 7.64% 23.8%
Los Angeles 53 609 112 1978 8.70% 5.66% 23.5%

The Leafs scored the most goals on the rush despite the fewest rush shots due to a vastly better shooting percentage (nearly 50% better than the Devils and Kings) on the rush. They do not generate more shots on the rush, but do seem to generate higher quality shots.

The Kings generate by far the most shots in non-rush situations but have the poorest shooting percentage and thus do not score a ton of goals. The Devils don’t generate many non-rush shots and don’t have a great non-rush shooting percentage either and thus posted the fewest goals. The Leafs have had the same number of shots as the Devils but a significantly higher shooting percentage than the Devils and thus scored significantly more non-rush goals.

The Leafs scored 34% of their goals on the rush compared to 32% for the Kings and 30% for the Devils.

Are the Leafs a good rush team? Well, only Boston has scored more 5v5 road rush goals than the Leafs so probably yes but it is mostly because of finishing talent, not shot generating talent. They are 4th last in 5v5 road rush shots.

The Ducks have very similar offense to the Leafs. They don’t get many rush shots but post a really high rush shooting percentage. Anaheim generate a few more non-rush shots than the Leafs but they are very similar offense.

The Kings are a slightly better rush team than the Devils but neither are good and both are weak shooting percentage teams regardless of whether it is a rush or non-rush shot. The Kings make up for this though by generating a lot of shots from offensive zone play where as the Devil’s don’t.

 

Jul 012014
 

The other day I commented on twitter that I would be happy if the Leafs signed defenseman Mike Weaver because I think he is a defensive defenseman that I think the Leafs could really use. I have thought of Mike Weaver as a premier defensive defenseman for quite some time now. I always seem to get a little flak over it but that’s fine, I can handle it. For example, as a response to my Weaver comment on twitter Eric Tulsky thought it would be prudent to point out a “flaw” in my thought process.

 

And of course, Tyler Dellow never passes up an opportunity to take a jab at me (or anyone who he disagrees with) took the opportunity to re-tweet it.

Now, of course I had thought of responding with a tweet to the effect of “Florida’s save percentage was probably is a bit of a factor in that regression” but I didn’t want to get into a twitter debate at that moment and I was confident I could come up with more concrete evidence. So here is that evidence.

SavePercentageWeaverOnOffIce

The above chart shows the save percentage of Weaver’s team when Weaver is on the ice vs when Weaver is not on the ice including only games in which Weaver has played in (i.e. it is better than just using team save percentage for that season and also allows us to combine his time in Florida and Montreal last season). As you can see, there has only been one season in the last 7 in which his team had a worse save percentage when he is on the ice than not. That is reasonably compelling evidence. It’s difficult to say what happened that season but his main defense partners were a young Dmitry Kulikov and Keaton Ellerby so maybe that was a factor. An investigation of Kulikov’s and Ellerby’s impact on save percentage over the years may help us identify why Weaver slipped that year. It could have been a nagging injury as well. Or, it could just be randomness associated with save percentage.

Regardless of the “reason” for the slide in 2011-12 it is pretty difficult to argue that there has been significant “regression” the past 3 seasons as Tulsky and Dellow so eagerly wanted to point out as the past 2 seasons Weaver has seemingly had a significant positive impact on his teams save percentage. Since I made that statement there has been one seasons of “regression” so to speak and two seasons in support of my claim. I guess that means it is 2-1 in my favour. It continues to appear that Weaver is a good defenseman who can suppress shot quality against.

Another defenseman I have identified as a defenseman who possibly can suppress opposition save percentage is Bryce Salvador. Here is Salvador’s on/off save percentage chart similar to Weaver’s above (2010-11 is missing as Salvador missed the season due to injury).

SavePercentageSalvadorOnOffIce

Salvador’s on-ice save percentage has been better than the teams save percentage every year since 2007-08. Regression? Doesn’t seem to be.

To summarize, there are a lot of instances where if we simply do a correlation of stats from one year to the next or  make observations of future performance relative to past performance we see the appearance of regression. In fact, the raw stats do in fact regress. That doesn’t necessarily mean the talent doesn’t exist, just that we haven’t been able to properly isolate the talent. The talent of the individual player is only a small factor in what outcomes occur when he is on the ice (a single player is just one of 12 players on the ice during typical even strength play) so it is difficult to identify without attempting to account for these other factors (quality of team mates in particular).

Possession and shot generation/suppression is important, but ignore the percentages at your peril. They can matter a lot in player evaluation.

 

Jun 122014
 

The rumour is out there that Sunny Mehta has been hired as Director of Hockey Analytics of the New Jersey Devils (if true, a big congrats to Sunny). This sparked some twitter discussion about the Devils and analytics and Devils defensemen including Bryce Salvador.

I have been a bit of a fan of Salvador, at least statistically, though clearly there are a lot of Devils fans that do not like him and I think it is because of a focus on corsi. One person tweeted me an image of Salvador’s corsi rel % suggesting it was “pretty ugly”. While maybe true the game isn’t about Corsi it is about goals. Here is what I know about Salvador. In 5v5close situations he led the Devils defensemen in on-ice save percentage last season, the season before, and the season before that. He missed 2010-11 due to injury but in 2009-10 he was second best trailing only Andy Greene, his regular defense partner. Either he is extremely lucky (every year) or he is doing something right.

Lets look at this a different way. Over the past 3 seasons Bryce Salvador has had the third best 5v5close save percentage in the league when he is on the ice despite the Devils ranking 23rd in team save percentage. The two players ahead of him play for Boston (Dougie Hamilton) and Los Angeles (Willie Mitchell) who have significantly better goaltending (3rd and 8th best 5v5close save percentages over past 3 seasons) and again, they played in front of far better goaltending.

In February 2012 I wrote an article attempting to quantify a defenders effect on save percentage and in it I identified Salvador as one of the best defensemen at boosting his teams save percentage. In the 2 seasons since he has done nothing but support that claim.

So, what does this all mean? Well, it takes a player who had a team worst 15.9 CA/20 in 5v5close situations this past season to a team best 0.49 GA/20.  Over the past 3 seasons only Dougie Hamilton (Boston), Willie Mitchell (Los Angeles) and Alec Martinez (Los Angeles) have seen goals scored against them at a lower rate than Bryce Salvador.

I know the majority of people are on the corsi bandwagon these days and some will dismiss any argument that runs counter to it but I think the evidence is clearly on Salvador’s side here. All evidence suggest he is really good as suppressing opposition shot quality and in turn suppressing the number of goals scored against the Devils. If I were the new Director of Hockey Analytics for the Devils I wouldn’t be recommending getting rid of Salvador.