Jan 232013
 

One of the challenges in hockey analytics, or any type of data analysis, is how to best visualize data in a way that is exceptionally informative and yet really simple to understand. I have been working on a few things can came up with something that I think might be a useful tool to understand how a player gets utilized by his coach.

Let’s start with some background. We can get an idea of how a player is utilized by looking at when the player gets used and how frequently he gets used.  Offensive players get more ice time on the power play and more ice time when their team is trailing and needs a goal. Defensive players get more ice time on the PK and when they are protecting a lead. This all makes sense, but the issue is some teams spend more time on the PP or PK than others while bad teams end up trailing more than good teams and leading less. This means doing a straight time on ice comparison between players on different teams doesn’t always accurately depict the usage of the player. If a player on the Red Wings plays the same number of minutes with the lead as a player on the Blue Jackets it doesn’t mean the players are used int he same way.  The Blue Jackets will lead a game significantly less than the Red Wings thus in the hypothetical example above the Blue Jackets are depending on their player a higher percent of the time with a lead than the Red Wings are their player.

To get around this I looked at percentages. If Player A played 500 minutes with a lead and his team played a total of 2000 minutes with a lead during games which Player A played, then Players A’s ice time with a lead percentage would be 25%. In games in which Player A played he was used in 25% of the teams time leading. I can calculated these percentages for any situation from 5v5 to 4v5 or 5v4 special teams to leading and trailing situations. The challenge is to visualize the data in a clear and understandable way. To do this I use radar charts. Lets look at a couple examples so you get an idea and we’ll use players that have extreme and opposite usages: Daniel Sedin and Manny Malhotra.

For those not up to speed on my terminology f10 is zone start adjusted ice time which ignores the 10 seconds after a face off in either the offensive or defensive zone.

The charts above are largely driven by PP and PK ice time but players that are used more often in offensive roles will have their charts bulge to the top and top right while those in more defensive roles will have their charts bulge more to the bottom and bottom left. Also, the larger the ‘polygon’ the more ice time and more relied on the player is. In the examples above, Sedin is clearly used more often in offensive situations and clearly gets more ice time.

Let’s now look at a player who is used in a more balanced way, Zdeno Chara.

That is a chart that is representative of a big ice time player who plays in all situations. We can then take it a step further and compare players such as the following.

In normal 5v5 situations Gardiner was depended on about as much as Phaneuf, but Phaneuf was relied on a lot more on special teams and a bit more when protecting a lead. Of course, you can also compare across teams with these charts:

Phaneuf and Chara were depended on almost equally in all situations except on the PP where Phaneuf was used far more frequently.

I am not sure where I will go with these charts but I think I’ll look at them from time to time as I am sure they will be of use in certain situations and I have a few ideas as to how to expand on them to make them even more interesting/useful.

 

Feb 212012
 

There was a twitter conversation between Gabe Desjardins and David Staples last night in which Gabe suggested that Daniel Sedin’s heavy offensive zone start bias resulted in an additional 7-9 points that he would not have gotten if his zone starts were more evenly split between offensive and defensive zone.  When I saw this I immediately though that seemed like a really high number so I decided to take a look though the play by play sheets and see how many of Daniel Sedin’s even strength points came from a faceoff in the offensive zone.  Of all of Daniel Sedin’s points so far, here are the only ones that might at all be attributed to an offensive zone faceoff.

Date Opppnent Type Time After Faceoff
Oct. 15 Edmonton Assist 8 seconds
Oct. 20 Nashville Goal 11 seconds
Oct. 29 Washington Assist 19 seconds
Nov. 29 Columbus Goal 8 seconds
Dec. 6 Colorado Goal 24 seconds
Jan. 31 Chicago Goal 29 seconds
Feb. 18 Toronto Assist 40 seconds

Every other point that Daniel Sedin got was either on the PP, after a faceoff in another zone or after a line change during the play or after the opponent had possession of the puck.  Even the points above we don’t know if the opposition had control of the puck between the faceoff and the goal, especially for the plays 19 seconds or longer after the faceoff (a lot can happen in 19 seconds) and the goal vs Colorado was during 4 on 4 play as well.  But for the sake of argument, let’s say we can directly tie all 7 of those points to being a result of offensive zone face offs.  Also, for the sake of easy math, let’s assume his OZone% is 70% (it’s actually closer to 80%).  So, on 70% OZone starts he scored 7 goals.  If we reduce his Ozone% to 50% you’d naturally think you’d lose an equivalent portion of points so he’d end up with 5 points instead of 7.  Net result, Daniel Sedin’s offensive zone start bias has accounted for just 2 additional points so far this season.

What about previous seasons?  Well, over the previous 3 seasons Daniel Sedin was on the ice for 197 5v5 goals for.  If we ignore the 30 seconds following an offensive or defensive zone start (and 30 seconds is more than ample to account for zone starts) he was on the ice for 151 goals for.  That means we can fairly safely assume that offensive zone starts at best resulted in 46 goals for.

Now, over the past 3 seasons Daniel Sedin was on the ice for 1164 offensive zone face offs and 656 defensive zone face offs for an OZone% of about 64%.  Those 1164 offensive zone faceoffs accounted for at most 46 goals meaning approximately every 25 offensive zone starts resulted in a goal.  If Sedin had a 50% OZone% over the previous 3 seasons instead of his 64% he’d have been on the ice for about 910 offensive faceoffs, or about 254 fewer than he actually had.  Since every 25 offensive zone starts results in a goal those 254 extra offensive zone face offs he took resulted in approximately 10 extra goals being scored.  So, on average Daniel Sedin was on the ice for 3-4 extra goals per season because of his offensive zone faceoff bias, and that is being generous with the math.  That result is not far off this seasons observations above.

So, considering one of the best offensive players in the game with one of the most significant offensive zone biases in the game is only on the ice for at most an additional 4 goals a season as a result of their offensive zone bias, I think we can chaulk up the zone start effect as mostly insignificant.  The majority of players aren’t near as talented as D. Sedin and his linemates are and the majority of players end up having between 45% and 55% zone starts.  As a result, the majority of the players probably only see a zone bias affect their stats by at most one or two goals a season.  It’s pretty much not worth consideration.

Of course, a corsi based analysis would show a more significant difference because zone starts affect corsi more than goals.

 

May 042011
 

I am going to combine the Vezina and Hart trophy discussion into one post because the Vezina discussion is going to be fairly short because I actually agree with the nominees.

The three nominees for the Vezina trophy are Roberto Luongo, Tim Thomas and Pekka Rinne.  These are the top 3 goalies in terms of overall save percentage (Thomas first, Rinne second, Luongo third), goals against average (Thomas first, Luongo second and Rinne third) and rank 1, 3 and 4 in my HARD+ 5v5 even strength ratings for goalies with over 2500 5v5 minutes (Thomas first, Rinne third, Luongo fourth).  Incidently, over the past 4 seasons these are the three highest rated goalies for HARD+ for goalies with over 7500 minutes of 5v5 ice time (Thomas first, Luongo second, Rinne third).  These three goalies are probably the top 3 goalies in the NHL today with Thomas leading the pack  Thomas is most deserving of the Vezina trophy this season.

The HART trophy is a little more interesting.  The three nominees are Daniel Sedin, Martin St. Louis and Corey Perry.  Let me address each of these three individually.

Corey Perry – A couple weeks ago I write an article explaining why I didn’t think Corey Perry was as valuable to the Ducks this season as in past seasons.  In short, while Perry put up some great individual numbers and anyone who scores 50 goals in the NHL is doing something right, he accomplished this at the expense of his line mates and his overall team performance.  Of the 116 players with greater than 1000 even strength 5v5 minutes Corey Perry ranked 46th in HARO+ (1.164), 90th in HARD+ (0.852) and just 69th in HART+ (1.008).  Great individual numbers but his teammates performed better when not with him.  Is that indicative of someone deserving the title of “Most Valuable Player”?  I don’t believe so, though I believe there is a great chance he’ll win because he scored 50 goals and put up big numbers down the stretch to help the Ducks make the playoffs.

Martin St. Louis – St. Louis had another great season and I do believe that St. Louis is the most important player for the Tampa Bay Lightning, and has been for many years now.  Overall he ranked 16th in HARO+ (1.335), 36th in HARD+ (1.022) and 14th in HART+ (1.179).  I would not suggest that he is a bad nominee, but there might be better ones.

Daniel Sedin – Of the three nominees, Daniel Sedin is the only one I would consider listing as a top three candidate.  He ranked  a close second (to Nathan Horton) in HARO+ (1.474), ranked 13th in HARD+ (1.135) and ranked fourth in HART+ (1.305).  The only negative against Sedin is that there are many other players who play against better competition.  Sedin’s opposition goals for ratio is just .501 which is well below some others worthy of HART trophy consideration.

Here are a handful of others I would consider worthy of HART trophy consideration:

Jonathan Toews – Toews has the third best HARO+ (1.465), the 17th best HARD+ (1.117) and ranked 5th in HART+ (1.291).  Toews numbers are very close to Daniel Sedin’s but it can be easily argued that Toews played against tougher competition (.509 opposition goals for percentage vs Sedin’s .501) and unlike Sedin, Toews kills penalties too.

David Backes – Backes scored 31 goals and 62 points and led all NHL forwards with a +32 rating (one behidn league leader Chara) and he did this on a weak St. Louis Blues team and like Toews, he also plays when the team is short handed.  If he played with better players his individual stats would likely be much better but because he plays on a weak team his performance largely gets unnoticed.  What is impressive is he accomplished this while having the highest opposition goals for per 20 minutes and goals for percentage.  Backes’ performance puts him 4th in HARO+ (1.449), 9th in HARD+ (1.199) and  second overall in HART+ (1.322).  By all acounts Backes had a great season, even if the goal and point totals don’t quite match the league leaders.

Anze Kopitar – I am not sure if everyone realizes how good of a 2-way player Kopitar is.  He puts up good offensive numbers but he  has also defensively sound and kills penalties.  This past season he ranked 10th in opposition goals for per 20 minutes and ranked 15th in opposition goals for percentage so he is trusted to play against the leagues best players and the results are there to back that up.  This past season Kopitar ranked 5th in HARO+ (1.427), 4th in HARD+ (1.239) and first in HART+ (1.333).

The problem with HART trophy voting is they largely choose players who put up the best individual offensive numbers but in general they neglect to take into account defensive ability and responsibility.  In Toews, Backes and Kopitar we have three quality offensive players who also play solid defensive games against top players in the NHL and are given the responsibility to kill penalties.  The other player I would suggest is worthy of consideration for the HART trophy is Zdeno Chara who was clearly the best defenseman in the NHL this past season as I discussed in yesterdays Norris Trophy post.

So with all that said, I expect that Sedin or Perry will win but my top five HART trophy candidates would be: Daniel Sedin, Jonathan Toews, Zdeno Chara, Anze Kopitar and David Backes and if pushed to make a pick I’d probably choose Sedin ever so slightly over Toews and Chara.

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Jun 192009
 

I have written a lot about the Phoenix Coyote situation the past several weeks so let me get back to addressing some hockey issues.

Dany Heatley

Wow, this guy is getting lambasted here in Ottawa for asking for a trade. Two years ago at this time he was a hero in Ottawa coming off back to back 50 goal seasons and a run to the Stanley Cup finals but now he is being compared to Alexei Yashin. If I were a Sens fan I might actually consider this trade request a good thing as it will give GM Bryan Murray an opportunity to change a top heavy team with no real second line and an average defence into a more balanced team. But he has to make the right deal which may or may not be out there, and certainly may not be available prior to Heatley getting a $4 million bonus on July 1st. There are two routes that I could see Bryan Murray going. The first, which is probably the better route to go in my opinion, is to trade Heatley for prospects and draft picks and then use the freed up salary cap space to sign 2-3 useful free agents to plug holes on the current roster. The second route would be to trade Heatley for current NHL players. It was speculated that the Edmonton Oilers might be willing to trade defenseman Tom Gilbert and forward Patrick O’Sullivan but if that is the best you can get in return I’d definitely suggest Murray go the prospect and draft pick route. While Gilbert is a pretty good defenseman and would fill a need for the Senators, O’Sullivan hasn’t impressed me much at all early in his career and it would makes Ottawa’s offense even shallower than last year. Plus the salaries of those two players wouldn’t add much extra salary cap space to sign a quality offensive forward as a free agent. It’ll be interesting how this pans out but.

The Sedin Twins

We learned yesterday that the Sedin Twins have each asked for a 12 year, $63 million contract which works out to a $5.25 million salary cap hit per year. There seems to be a general negativity towards the Sedins asking for this much for this long but is it deserved? Henrik Zetterberg recently signed a 12 year contract with the Red Wings at $6.08 million and Johan Franzen signed an 11 year contract at just under $4 million per season. A couple years ago the Philadelphia Flyers signed Mike Richards to a 12 year contract at a $5.75 million cap hit. Here are each players 2-year averages:

Zetterberg: 76gp, 37g, 82.5pts
Franzen: 71.5gp, 30.5g, 48.5pts
Richards: 75gp, 29g, 77.5pts
D. Sedin: 82gp, 30g, 78pts
H. Sedin: 82gp, 18.5g, 78pts

In terms of point goal and point production, Daniel Sedin is almost identical to Mike Richards despite Richards playing on a more offensive oriented team. The Sedin’s have been remarkably consistent over the past 4 seasons (post lockout) as well. Henrik has had 75, 81, 76 and 82 point seasons and Daniel has had 71, 84, 74 and 82 point seasons and combined they have missed just one game (Daniel in 2006-07). Additionally, both players have been + players ever year of their careers except their rookie seasons. Considering all of this, I honestly don’t think that the Sedin’s request is all that out of line. Steve has more on the Sedin’s request while Jason seems a little outraged.

NHL Awards

I didn’t watch the awards and am not going to comment on them other than to say I think they should be handed out in a location where at least a small percentage of the citizens know who Zdeno Chara is let alone know what the Norris Trophy is for.

Steve Simmons on Balsillie

Ok, so I can’t completely ignore the Coyotes situation in this but consider this more of a Steve Simmons bash than a Coyotes discussion. In today’s article Simmons wrote:

In the online letter to Bettman, that Canadian fans were asked to click on and send, it read: “It is clear Hamilton remains the best location for the Coyotes versus letting it wither in the desert.”

This may well be true, but it’s no way of conducting business.

You just have to love Steve Simmons, the often nonsensical and seemingly always bitter hockey journalist, handing out business advice to the multi-billionaire businessman who built one of the most successful telecom companies in the world.