Sep 182014
 

Earlier this week TSN announced the creation of an Analytics team consisting of long-time TSN contributor Scott Cullen along with new TSN additions of Globe and Mail’s James Mirtle and hockey blogger Travis Yost. I am all for main stream media jumping on board with hockey analytics but once you go from independent hockey blogger to a significant contributor to TSN I think it opens the door to higher expectations and higher standards.  Scott Cullen has a long track record with TSN and I am confident James Mirtle will bring some intelligent insight as we are all familar with and respect his work. While I am fully aware of Yost and his blogging history I have to be honest in saying that I have not read a ton of his stuff so I was interested to see what he would offer. After reading his first two articles, I have to say I definitely think there is room for improvement.

Yost’s first article was a look at some trends as to how teams use players during 5 on 5 play. The point I think Yost was trying to make most is that teams are phasing out goons and other “specialists” and replacing them with guys that can play bigger minutes and at both ends of the rink. While this may very well be true I am not sure Yost’s evidence to support this is really valid. He produced a chart that showed that more players are getting more 5v5 ice time per game in 2013-14 than in 2007-08 and his conclusion was that this was evidence of teams moving away from goons and small ice time players.

The rightward shift here should seem apparent – a higher concentration of guys playing larger minutes now as opposed to seven years ago and fewer guys picking up scrap minutes in smaller roles. The number of forwards playing ten or less minutes a night has dropped from 109 in 2007, to 65 in 2014. And the number of forwards playing between 13 and 16 minutes a night has moved from 153 in 2007 to 231 in 2014. As a group, teams may still be leaning on their star players, but there’s also been a more balanced spread of total ice time than there was seven years ago.

First off, the rightward shift that Yost talks about is likely almost exclusively due to the fact that there were far fewer penalties and power plays in 2013-14 than there were in 2007-08 as Yost pointed out earlier. This lead to there being more even strength ice time to be doled out to the same number of players. This will almost certainly produce a right shift as observed. As for a more balanced spread in ice time, I don’t see that either. At least not to any significant extent. If one really wanted to look at this properly instead of looking at number of minutes of even strength ice time played one would want to look at percentage of a teams even strength minutes the player played. This would eliminate the difference in total even strength ice time and truly allow you to see whether teams are using a more balanced line up or not. At the very least one should adjust each players ES TOI by an appropriate amount for one of the seasons based on the ratio of league-wide ES TOI between the two seasons. I’d then be interested to see if a “right shift” occurs or whether there is a meaningful difference in the charts.

Yost’s second article for TSN.ca was about Marc-Edouard Vlasic and how he should probably be getting more recognition for how good he really is. Now that is a sentiment I can generally support but Yost’s supporting evidence for this is analytically unsound in my opinion. The first thing Yost does is identify a number of defensemen who are generally considered the leagues best that we should compare Vlasic too. This is a good start and Yost identified guys like Chara, Doughty, Karlsson, Pietrangelo, Subban, etc. What Yost did next is produce a bubble chart that plots even strength corsi% on the x-axis vs even strength goals % on the y-axis with bubble size representing scoring production. To be honest, I have no clue what the value of this chart is. Both corsi% and goal% are significantly  team driven but there was no accounting for quality of team and goal% has a certain amount of luck and randomness associated with it which was not discussed and I really have no idea what statistic was used for scoring production. The conclusion Yost drew from this chart was that Vlasic was right in the mix with some of the best defensemen in the league. Problem is I am certain I could find a number of other defensemen we generally consider mediocre that would be right there with Vlasic.

There are proper ways to do this kind of analysis and there is no way one can do this without taking into consideration quality of teammates. On my stats site I have teammate statistics (denoted by TM) and one can easily do a comparison of how the players on-ice stats compare to their teammates when their teammates are not playing with them. Doing this we get the following:

Player Name CF60 RelTM
ERIK KARLSSON 9.115
DUNCAN KEITH 8.597
ALEX PIETRANGELO 8.202
MARK GIORDANO 6.695
P.K. SUBBAN 6.152
MARC-EDOUARD VLASIC 5.87
SHEA WEBER 2.072
RYAN MCDONAGH 2.032
DREW DOUGHTY -0.448
ZDENO CHARA -0.55
RYAN SUTER -1.518

If we use CF60 as a proxy for offensive production we find the best offensive defensemen are Karlsson, Keith and Pietrangelo while the least offensive are Suter, Chara and Doughty. Vlasic is right in the middle and looks pretty good. One might be surprised at Doughty but the rest kind of make sense.

Now, let’s do the same for CA60.

Player Name CA60 RelTM
MARK GIORDANO -12.251
MARC-EDOUARD VLASIC -9.205
P.K. SUBBAN -4.586
ERIK KARLSSON -2.21
ZDENO CHARA -1.69
DREW DOUGHTY -1.585
ALEX PIETRANGELO -0.211
RYAN SUTER 0.953
DUNCAN KEITH 2.385
SHEA WEBER 4.34
RYAN MCDONAGH 4.468

For CA60 it is better to have a negative number as this indicates you are giving up fewer shot attempts than your teammates when they aren’t playing with you. Here Vlasic is second and looking pretty good.

Now we can combine these two stats by looking at CF% RelTM.

Player Name CF% RelTM
MARK GIORDANO 8.9%
MARC-EDOUARD VLASIC 6.6%
P.K. SUBBAN 4.8%
ERIK KARLSSON 4.6%
ALEX PIETRANGELO 3.7%
DUNCAN KEITH 2.3%
DREW DOUGHTY 0.7%
ZDENO CHARA 0.6%
SHEA WEBER -1.0%
RYAN SUTER -1.2%
RYAN MCDONAGH -1.2%

Out of this group, Vlasic is second best which is pretty good and is evidence that he probably deserves to be in the company of these guys. Now, with that said, this is just a cursory look and in no way a complete analysis. Not only are there limitations by just looking at corsi but there are a lot of other factors that need to be taken into consideration as well (for example, Giordano is probably not that good, only looks good because his Flames teammates are not very good relative to the teammates of the other players on this list). Overall though, this is how I think one should start an analysis of Vlasic and whether he deserves more credit for the player he is. To be fair to Yost, he gets into this a little bit by looking at a timeseries of Vlasic’s Relative Corsi% but in no way is this sufficient and he doesn’t compare it to any of the other defensemen he is comparing Vlasic to.

Overall I applaud TSN for wanting to jump on the analytics band wagon and I am certain Yost has the potential to provide a better analytical view than his first few posts which, to be honest, left me a little underwhelmed if not disappointed.

On the flip side, I saw some good stuff written recently by @MimicoHero that I think is worthy of mention. A recent blog post of his looked at Ryan Johansen’s value to the Blue Jackets and he, in my opinion, did a pretty good job of accounting for usage (i.e. QoT, QoC, zone starts) and comparing Johansen to his peers. I like the tables he produced and how he looked at offense and defense separately. Now I’d probably want to weight QoT far more heavily in the usage metric he came up with but overall a very good methodology for comparing players on different teams playing in different circumstances.

 

Jul 022014
 

The other day I looked at the effect that Mike Weaver and Bryce Salvador had on their teams save percentage (if you haven’t read it, definitely go give it a read) when they were on the ice versus when they weren’t on the ice. Today I am going to take a look at the Maple Leaf defensemen to see if there are any interesting trends to spot. We’ll start with the new acquisitions.

Stephane Robidas

RobidasOnOffSavePct

(Blue line above orange is good in these charts, opposite is not good)

Aside from 2008-09 he has had a negative impact on his team save percentage. In 2007-08, 2009-10 and 2010-11 his main defense partner was Nicklas Grossman but in 2008-09 his main defense partner was Trevor Daley. Did this have anything to do with his poor effect on save percentage in 2008-09? Well, aside from last season Daley’s on-ice save percentage has been at or better than the team save percentage so there might be something to that.

Roman Polak

PolakOnOffSavePct

Not really a lot happening there except in 2011-12 when he was worse than the team (and the team had significantly better goaltending). Rembember though, the Blues have a pretty good defense so it is quite possible that not being worse than the rest of them is a good thing. Will be interesting to see how he does in a Leaf jersey this season.

Dion Phaneuf

PhaneufOnOffSavePct

Aside from 2008-09 there has been a slight positive impact on save percentage when he is on the ice. In 2008-09 he didn’t have a regular defense partner. At 5v5 he played a total of 1348:08 in ice time and his main defense partners were Giordano (364:56), Vandermeer (342:47), Pardy (304:27), Leopold (163:47), Regehr (85:08) and Sarich (77:41). That variety in defense partners can’t be a good thing. But, maybe Phaneuf has a slight positive impact on save percentage.

Cody Franson

FransonOnOffSavePct

So, he was good for a few years and then he was bad. What happened? Well, he was traded to the Leafs. For the 2009-10 and 2010-11 seasons his main defense partner was Shane O’Brien and he also spent significant time with Hamhuis. This could be a case of him playing “protected” minutes as he had really easy offensive QoC but I generally don’t think QoC has anything near as significant an impact as other factors so I am not sure what is going on. He has had pretty weak QoC the last couple seasons too so who knows.

Jake Gardiner

GardinerOnOffSavePct

It is only 3 seasons of data but so far so good for Gardiner. He has been a boost to the teams save percentage and that is on top of his good possession numbers. In my opinion, Gardiner is quite likely the best defenseman. I’ll drop the “quite likely” from that statement when he repeats his success but against tougher QoC as that will remove any doubt.

Now, let’s take a look at a couple of departing Leaf defensemen.

Carl Gunnarsson

GunnarssonOnOffSavePct

Save for 2010-11 Leaf save percentage has been better whith Gunnarsson on the ice. His two main defense partners that year were Luke Schenn and Mike Komisarek so maybe we can forgive him. In 2009-10 his defense partner was mainly Beauchemin or Kaberle and starting in 1011-12 it has mainly been Phaneuf.

Tim Gleason

GleasonOnOffSavePct

Tim Gleason gets a lot of criticism from Leaf fans, the analytics community, and maybe pretty much everyone but his teams have generally had a positive boost in save % when he is on the ice and in some cases a significant boost.

Based on the loss of Gunnarsson and Gleason, two defenseman who seem to be able to boost on-ice save percentage, and the addition of Robidas who has a negative impact and Polak who has more neutral impact it is quite possible the Leafs suffer a drop off in save percentage this season.

That said, I am not certain what to make of the impact we see and why they occur. Of the 9 defenseman I have presented charts for the past few days (the 7 above as well as Weaver and Salvador in my previous post) it seems that the majority of them have all but one or two of their seasons consistently boosting or inhibiting their teams save percentage. More investigation is needed as to why but I am becoming fairly confident that this is a repeatable talent. There is just too much consistency to consider it purely random.