Mar 152013

A few people didn’t like that I suggested that Jay McClement was a bad player in yesterday’s Mikhail Grabovski post so I thought I would provide a visual representation of McClement’s  mediocrity in the form of 5v5 Zone Start adjusted CF% WOWY charts for each of the past 6 seasons (this season included).

Let’s start with this current season even though the sample size is relatively small and so the number of line mates with a reasonable number of minutes with McClement is relatively small.


In this chart, it is better for McClement to have the bubbles below and to the right of the diagional line indicating his teammates corsi for % improved when they were on the ice with McClement. As you can see, none did.

So, what about previous seasons?

Continue reading »

Feb 212013

Over the past few years I have had a few discussions with other Leaf fans about the relative merits of Francois Beauchemin. Many Leaf fans argue that he was a good 2-way defenseman who can play tough minutes and is the kind of defenseman the Leafs are still in need of. I on the other hand have never had quite as optimistic view of Beauchemin and I don’t think he would make this team any better.

On some level I think a part of the difference in opinion is that many look at his corsi numbers which aren’t too bad but I prefer to look at his goal numbers which have generally not been so good. So, let’s take a look at Beauchemin’s WOWY numbers and see if there is in fact a divergence between Beauchemin’s corsi WOWY numbers and his goal WOWY numbers starting with 2009-11 5v5 WOWY starting with CF% WOWY.


I have included a diagonal line which is kind of a ‘neutral’ line where players perform equally well with and without Beauchemin. Anything to the right/below the line indicates the player played better with Beauchemin than without and anything to the left/above they played worse with Beauchemin. As you can see, the majority of players had a better CF% with Beauchemin than without. Now, let’s take a look at GF% WOWY.


While a handful of players had better GF% with Beauchemin, the majority were a little worse off. There is a clear difference between Beauchemin’s CF% WOWY and his GF% WOWY. What is interesting is this difference can be observed in 2007-08, 2009-10, 2010-11, and 2011-12 (he was injured for much of 2008-09 so his WOWY data is not reliable due to smaller sample size). Looking at his 5-year WOWY charts you get a clear picture that Beauchemin seemingly has a skill for ‘driving play’ but not ‘driving goals’. Let’s dig a little further to see if we can determine what his ‘problem’ by looking at his 2009-11 two year CF20, GF20, CA20 and GA20 WOWY’s.





As you can clearly see, Beauchemin appears to be much better at generating shots and shot attempts than he is at generating goals. The majority of players have a higher corsi for rate when with Beauchemin than when not with Beauchemin but the majority also have a lower goals for rate. What about ‘against’ rates?





For CA20 and GA20 is is better to be to be above/left of the diagional line because unlike GF%/CF%/GF20/CF20 it is better to have a smaller number than a larger number. There doesn’t seem to be quite as much of a difference between CA20 and GA20 as with CF20 and GF20 so the difference between CF% and GF% is driven by the inability to convert shots and shot attempts into goals as opposed to the defensive side of the game. That said, there is no clear evidence that Beauchemin makes his teammates any better defensively.

There are two points I wanted to make with this post.

  1. Leaf fans probably shouldn’t be missing Beauchemin.
  2. For a lot of players a corsi evaluation of that player will give you a reasonable evaluation of that player but there are also many players where a corsi evaluation of that player will not tell the complete story. Some players can consistently see a divergence between their goal stats and their corsi stats and it is important to take that into consideration.


Oct 292012

The other week I wrote about breaking down IPP (Individual Point Percentage, which is individual points divided by number of goals scored while the player was on the ice) into IGP (Individual Goal Percentage) and IFAP (Individual First Assist Percentage).  It seems IGP does a decent job of identifying the pure goal scorers and IFAP does a decent job of identifying the pure play makers.  I have always been interested in team/line makeup and how to maximize a lines performance so I decide to take a look at WOWY IPP comparisons for two pairs of extremely talented players who have at times played together and at times played on separate lines the past 5 years.  These are Crosby/Malkin and Thornton/Marleau.  Let’s start with Crosby/Malkin.

Crosby without Malkin 2527:07 35.7% 36.3% 84.7% 1.33 1.35 1.24
Crosby with Malkin 954:29 41.9% 30.2% 91.9% 2.26 1.63 1.80
Malkin without Crosby 3588:42 32.2% 38.3% 86.7% 0.97 1.15 1.00
Malkin with Crosby 954:29 27.9% 30.2% 75.6% 1.51 1.63 1.80

These two players have played significantly more ice time apart than with each other but still the comparison is interesting.  When separated Crosby IGP and IFP are very close together indicating he is relatively balanced between being a goal scorer and a playmaker but when he is playing with Malkin he becomes a more important goal scorer as his IGP rises from 35.7% without Malkin to 41.9% with Malkin and his IFAP falls from 36.3% without Malkin to 30.2% with Malkin.  Crosby got a point on 84.7% of all goals scored while he was on the ice without Malkin which is a very high number, but it rises to 91.9% when he is playing with Malkin which is a truly extraordinary number.

Malkin, strangely, sees both his IGP and his IFAP fall when playing with Crosby which means a smaller percentage of the goal production goes through Malkin when Crosby is on the ice. This makes sense since Crosby is in on nearly every goal scored when the two are on the ice together.  Interestingly, despite being in on a lower percentage of goals, Malkin did see his individual G/60 and individual FA/60 rise dramatically when playing with Crosby due to the fact that when those two are on the ice together they score goals at an exceptionally high rate.

I am not sure what to conclude here other than if you desperately need to score a goal late in the game it would be awfully smart to play these two together.  But, with that said, it may not be the most prudent use of resources during the course of the game because it seems to somewhat diminish Malkin’s ability to drive the play.  Now, lets take a look at Thornton/Marleau.

Thornton without Marleau 2585:10 24.6% 35.2% 79.6% 0.75 1.07 1.01
Thornton with Marleau 2438:22 19.3% 37.8% 74.8% 0.64 1.25 1.11
Marleau without Thornton 2808:03 32.3% 24.2% 69.7% 0.74 0.56 0.77
Marleau with Thornton 2438:22 37.8% 13.3% 73.3% 1.25 0.44 1.11

This shows that Thornton and Marleau are very different players.  Marleau is clearly much more of a goal scorer while Thornton is clearly much more of a play maker, and this is true regardless of whether they are playing together or apart.  When playing with Marleau Thornton sees his goal production drop from 0.75 G/60 to 0.64 G/60 but his FA/60 rise from 1.07 to 1.25.  For Marleau his G/60 rises significantly when playing with Thornton but his FA/60 falls a bit too and his IFAP falls to an astonishingly low 13.3%.  In short, Marleau’s goal production benefits a lot from playing with Thornton, while Marleau’s benefit to Thornton is a little less significant.  I believe if we continued this analysis to Thornton’s other line mates we will find that Thornton’s play making skills are easily the most significant driving force of the Sharks offense.

Having done this IPP WOWY comparison for these two pairs of players we can make some interesting observations and we can get a better idea of which player is driving the play when they are playing together (and apart).  That said, I think more work needs to be done to determine whether IPP WOWY is a useful player evaluation tool in general, or just something that might be interesting to look at in certain situations.  I’m curious what others think, or if you have another pair of players you want me to look at let me know (for example, Spezza/Alfredsson might be interesting).


Jun 152012

One of the top NHL unrestricted free agents this summer is the Washington Capitals Alexander Semin.  Semin  has seen his goal production drop from 40 goals in 2009-10 to 28 in 2010-11 to post-lockout low of 21 this past season and as a result peoples general view of Semin’s value has dropped significantly.  The question is, what was the reason for his drop off in offensive stats.  Is it Semin alone, or is there some other underlying reason.

Let’s take a closer look at Semin’s point totals over the past 5 seasons.

Season GP G Pts PP Pts SH Pts ES Pts ES TOI ES TOI/Pt
2011-12 77 21 54 11 0 43 1097:23 25.5 min.
2010-11 65 28 64 18 1 45 904:38 20.1 min.
2009-10 73 40 84 27 2 55 1077:22 19.6 min.
2008-09 62 34 79 30 2 47 850:02 18.1 min.
2007-08 63 26 42 20 0 22 780:48 35.5 min.

When you strip out Semin’s even strength performance you begin to realize that his point total drop off is not near as significant.  The past 4 seasons he has had 47, 55, 45 and 43 even strength points.  Now his time on ice between points increased dramatically this season but a significant part of that is likely due to his line mates.  Three seasons ago Semin’s most frequent line mates were Brooks Laich, Nicklas Backstrom, Alexander Ovechkin and Tomas Fleishmann ordered by time on ice together.  Two seasons ago they were Laich, Backstrom, Ovechkin and Johansson.  This past season they were Johansson, Perreault, Chimera and Ovechkin.  No offense to Johansson, Perreault and Chimera, but they have combined for just one 40 point season in their careers, and that was Johansson this past season playing with Semin.  That certainly has a little to do with Semin’s drop off.

Another way to look at Semin is to take a look at how his team mates perform when they are on the ice with Semin and when they are on the ice without Semin.  We can do this by looking at some nice bubble charts.

The above chart has GF20 without Semin across the horizontal axis and GF20 with Semin across the vertical axis.  For those new readers, GF20 is goals for (i.e. scored by team) per 20 minutes of ice time.  The color of the circle identifies the year and the size of the circle indicates relative ice time played with Semin.  The larger the circle, the more minutes they played with Semin, the smaller the circle the fewer.  Each forward who played at least 150 minutes with Semin are shown above.

In this chart circles in the upper left indicate that Semin had the greatest impact on his team mates offensive performance as upper-left circles indicate they performed relatively poorly without Semin and relative well with Semin.  Anyone above the 1:1 diagonal line (not shown) means that they had a better GF20 with Semin than without.  As you can see, over the past 3 seasons there is significant evidence that Semin has made his line mates better.  That changed slightly this past season though.  While Chimera and Perreault had better GF20’s with Semin, Johansson and Ovechkin did not.

Now lets take a look at the same chart but for GA20 (goals against per 20 minutes of ice time.

In this table bubbles in the lower right or below the 1:1 line are good as this indicates the player had a lower GA20 with Semin than without.  Except for Ovechkin in 2010-11 the majority of the bubbles are pretty close to the  1:1 line or slightly below.  This would seem to indicate that Semin is not a defensive liability which is relatively rate for quality offensive players.  Frequently producing big offensive numbers comes at a cost of defensive performance but this does not seem to be true for Semin.

The final bubble chart I will look at is goals for percentage (GF%) which is simply goals for divided by goals for plus goals against.

GF% is like GF20, the higher the number the better, so like the GF20 bubble chart, bubbles in the upper left above the 1:1 line are better, especially if they are above 50% (i.e. more goals for than against).  Except for Ovechkin and Johansson this past season and Morrison in 2009-10, all players had a better GF% with Semin than without.  This clearly points to Semin having a significant positive impact on his teams performance.

Maybe the most impressive thing I can point out about Semin is his overall 2-way performance relative to the rest of the league.  Of 125 players with 2500 5v5 zone start adjusted minutes of ice time over the past 3 season, Semin ranks 5th in GF20 (trailing only D. Sedin, H. Sedin, Toews, and Stamkos) and he ranks 13th in GA20.  It truly is a rare combination (for example, the Sedin’s rank 28 and 38 in GA20, Toews 60th and Stamkos 105th).

All that said, it does appear that Semin had a slight drop off in 5v5 offensive performance this past season but without further evidence it would probably be fair to presume that that was a somewhat minor drop off from an otherwise exceptional 4 years and certainly wouldn’t be enough to scare me away from making a significant offer to him as an unrestricted free agent.  He’d be a worthy addition to any NHL team.


Should Leafs give up on Armstrong?

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May 182012

Over at, Cam Charron did a corsi-based analysis of Colby Armstrong and came up with mixed conclusions regarding his performance over the past several seasons.

So, causes? What caused a player with pretty good possession statistics in Atlanta to completely fall off the map in the last two seasons? System? Trust? Role? A flaw in advanced statistics when players move teams? Or was it just all the injuries that made it a lot tougher on Colby than we think?

I don’t know what the answers to those questions are, but instead of trying to answer then I thought I would take a look at Armstrongs underlying goal numbers look like.  Let’s first start off with a high level view by looking at his HARO+, HARD+ and HART+ ratings.

2011-12 Toronto 235:24 0.449 0.784 0.616
2010-11 Toronto 588:54 1.274 0.823 1.048
2009-10 Atlanta 837:31 1.118 0.948 1.033
2008-09 Atlanta 900:34 1.214 1.016 1.115
2007-08 Pit/Atl 766:46 1.160 0.812 0.986

Save for this past season, where he simply didn’t play enough to get a reliable rating, his HARO+ rating is awfully consistent and remarkably good.  Defensively he had one good season in Atlanta but generally speaking has been extremely sub-par.  The end result is his HART+ numbers are fairly solid and a net positive player overall.  Now lets look at his WOWY stats for players he has played 150 minutes with during a single season.  We’ll start with GF20 data.

Player Year w/ Armstrong wo/ Armstrong Diff
Boyce 2010-11 1.561 1.100 0.461
Versteeg 2010-11 1.148 0.537 0.611
Kane 2009-10 0.931 1.266 -0.335
Slater 2009-10 1.051 0.815 0.236
Peverley 2009-10 0.980 0.826 0.154
Reasoner 2009-10 0.628 0.656 -0.028
White 2009-10 1.049 0.782 0.267
Reasoner 2008-09 0.850 0.719 0.131
Peverley 2008-09 1.469 0.663 0.806
Christensen 2008-09 0.266 1.067 -0.801
Kozlov 2008-09 1.399 0.702 0.697
Perrin 2008-09 0.914 0.648 0.266
Kovalchuk 2008-09 1.390 0.953 0.437
Crosby 2007-08 1.699 1.125 0.574
Malkin 2007-08 1.474 1.147 0.327
Perrin 2007-08 0.944 0.634 0.310
Average 1.110 0.853 0.257

Of the 16 player seasons, there were only 3 where the player had a worse GF20 with Armstrong than without.  That’s pretty good and on average the improvement was 0.256, or about 30%.  He even seemed to make elite offensive players such as Croby, Malkin and Kovalchuk better.  It makes me wonder if Armstrong is contributing in the same way that the players I identified in my “Mixing Toughness with Skill” article did.  Armstrong himself is not an elite offensive player, but the things he does on the ice (retrieving pucks, causing distractions on the ice, drawing attention to himself, etc.) allow the skilled players to do more.

Now let’s take a look at GA20.

Player Year w/ Armstrong wo/ Armstrong Diff
Boyce 2010-11 0.739 0.880 -0.141
Versteeg 2010-11 1.059 0.832 0.227
Kane 2009-10 1.008 1.266 -0.258
Slater 2009-10 0.901 0.815 0.086
Peverley 2009-10 1.224 1.071 0.153
Reasoner 2009-10 0.733 1.006 -0.273
White 2009-10 0.525 0.956 -0.431
Reasoner 2008-09 0.464 0.790 -0.326
Peverley 2008-09 0.851 0.900 -0.049
Christensen 2008-09 0.888 1.115 -0.227
Kozlov 2008-09 0.600 1.130 -0.530
Perrin 2008-09 0.686 1.105 -0.419
Kovalchuk 2008-09 1.137 1.139 -0.002
Crosby 2007-08 0.809 0.783 0.026
Malkin 2007-08 1.053 0.918 0.135
Perrin 2007-08 0.944 0.965 -0.021
Average 0.851 0.979 -0.128

For GA20, negative numbers are good as they indicate fewer goals against.  Interestingly, in 11 of the 16 players seasons the players saw their GA20 drop when playing with Armstrong, though six of them occurred during his previously identified good defensive season of 2008-09 (he didn’t have any consistent line mates that year).  As an average, Armstrong’s teammates saw an a 0.128 drop in GA20, or about 13% which isn’t too shabby.

Now lets take a look at how this pans out in GF%.

Player Year w/ Armstrong wo/ Armstrong Diff
Boyce 2010-11 67.9% 55.6% 12.3%
Versteeg 2010-11 52.0% 39.2% 12.8%
Kane 2009-10 48.0% 50.0% -2.0%
Slater 2009-10 53.8% 50.0% 3.8%
Peverley 2009-10 44.5% 43.5% 0.9%
Reasoner 2009-10 46.1% 39.5% 6.7%
White 2009-10 66.6% 45.0% 21.7%
Reasoner 2008-09 64.7% 47.6% 17.0%
Peverley 2008-09 63.3% 42.4% 20.9%
Christensen 2008-09 23.1% 48.9% -25.8%
Kozlov 2008-09 70.0% 38.3% 31.7%
Perrin 2008-09 57.1% 37.0% 20.2%
Kovalchuk 2008-09 55.0% 45.6% 9.5%
Crosby 2007-08 67.7% 59.0% 8.8%
Malkin 2007-08 58.3% 55.5% 2.8%
Perrin 2007-08 50.0% 39.6% 10.4%
Average 55.5% 46.0% 9.5%

Only 2 times did a player have a worse GF% with Armstrong than without.  Evander Kane saw a marginal drop in 2009-10 and Erik Christensen saw a significant drop in 2008-09.  Most other players saw significant improvements in their GF%, including Kovalchuk, Crosby and Malkin so it seems that Armstrong is a net positive player.

Looking at the above numbers, I think you can firmly put me in the lets not trade away Armstrong just to dump his salary camp.  It is quite possible that the proper thing to do with Armstrong is, if he can get healthy, promote him to the second line with Grabovski and MacArthur and he might make them even better.  Interesting concept.