Friday, August 15, 2008

Defensemen and Opportunity

So much of a defenseman's offensive stats come from PP time, and their even strength points and +/- (and the underlying numbers that drive it) seem to be mostly of a reflection of the quality of opposition and context of their ice time. These are tough players to judge by the numbers.

Since the context is obviously very important to any skater, I thought I'd look at the number of extra faceoffs each Oiler defenseman took in his own end of the rink, over and above the ones in the good end. I think it is a very good measure of the toughness of ice time.

So, by way of example, Staios was on the ice for a whopping 117 more defensive zone faceoffs than ones in the offensive end of the rink. Greene was at the opposite end of the spectrum, on the ice for 14 more draws in the offensive end of the rink than the home end.

The pattern is obvious I think. More own zone draws, without offensive zone ones to balance them out ... that leads to worse numbers.

The sample correlation here between faceoff zone +/- and corsi +/- is very strong, 0.91. The only other team I checked was the Calgary Flames, and the pattern there seemed obvious to me as well, the correlation being .81 in that case. So I doubt that this is unique to the Oilers, I can't see where it would be different except possibly on teams with a wild disparity in talent levels between their blueliners.

So really the only guys who seem to be separating themselves from the pack at all here are Staios (good, this context considered) and Greene (bad, this context considered). With good marks to Pitkanen and Tarnstrom as well.

And Pitkanen and Gilbert may go on to be the type of player that create a few extra goals at evens every year as well, time will tell. Tarnstrom has never been able to repeat his big offensive year in PIT, but he's still been useful.

BTW: You can get the faceoff data here, and the corsi data (amongst other things) here. They take about a minute to load, and you can change the team abbreviation in the URL to check for other squads.

13 Comments:

Blogger PDO said...

Excellent stuff here Vic...


Any easy way to get it into Excel? I'd love to play around with these numbers a bit, but I don't really have any interest in manually inputting it all into Excel...

8/16/2008 12:53 pm  
Blogger Vic Ferrari said...

If you use the links above, it should output an HTML web page in your browser. Just block the entire table and copy it, then past it into Excel, which will automatically convert it into a spreadsheet table.

8/16/2008 1:27 pm  
Blogger Vic Ferrari said...

Also: timeonice just uses jersey numbers, so you'll have to use behindthenet.ca, or somewhere similar, to get the positions and names of the players.

8/16/2008 1:29 pm  
Blogger PDO said...

Weird.. wouldn't work before, but is now.

All good, happy to have this in a more accessible environment. As always, thanks for providing information like this Vic.

8/16/2008 2:21 pm  
Blogger Jonathan said...

This is excellent stuff, Vic. Thanks so much for putting this out there.

8/17/2008 9:34 am  
Blogger Vic Ferrari said...

No problem guys, glad to see that people are making use of it. Thanks really what I hope for.

As well, I checked the latest visitors page there yesterday, and see that a lot of people are struggling to guess the right team abbreviations. They are (and they must be in CAPS in the URL):

ANA
ATL
BOS
BUF
CAR
CBJ
CGY
CHI
COL
DAL
DET
EDM
FLA
L.A
MIN
MTL
N.J
NSH
NYI
NYR
OTT
PHI
PHX
PIT
S.J
STL
T.B
TOR
VAN
WSH

8/17/2008 2:56 pm  
Blogger Vic Ferrari said...

Also, the numbers that follow "first=" and "last=" in the URL, they are the NHL's official game numbers. And you can alter those to look at any part of the season.

For the regular season the NHL uses numbers in the 20000s. And there are 1230 games in an NHL season, so the range is 20001 to 21230.

You will see these numbers in the URL of the official documents you look at on NHL.com (play by play, gamesheets, shootout reports, etc.) and at the top of the sheets as well, I think.

8/17/2008 3:00 pm  
Blogger Bruce said...

As well, I checked the latest visitors page there yesterday, and see that a lot of people are struggling to guess the right team abbreviations.

One of the strugglers was me, trying to guess Tampa's three-character code w.r.t. a comment I was making on another blog about Chris Gratton. I tried "TAM", "TB" and "TBL", all without success. Turns out the real one is "T.B". Not exactly intuituve. Are these codes the NHL's doing?

And, any chance you'll ever make a home page with a simple point-and-click menu for us cyber-morons? As I mentioned elsewhere, this data is excellent, but the interface is troublesome.

8/18/2008 1:33 pm  
Blogger Vic Ferrari said...

Yeah Bruce, the teams with the periods (L.A, N.J, S.J etc) were some of the ones causing troubles, just generally they all were.

These abbreviations are the ones that NHL.com uses.

As for interactive menu thing ... probably one day. I probably should use MySQL as well, the scripts I write are brute simple.

Also you can change the URL for the faceoff thing, by adding an "x" in front of "faceoffs" ... that will show you where the shifts ended.

So http://timeonice.com/teamxfaceoffs.php?team=EDM&first=20001&last=20615 would give you the zone that a player's shifts ended in (not counting EV shifts that ended in goals), and this particular URL would be for the Oilers, and for the first half of the season.

8/18/2008 1:44 pm  
Blogger Black Dog said...

Been on vacation the last two weeks and dealing with the new baby Vic so haven't dropped by recently.

Just wanted to say thanks for all of this work - terrific stuff as always.

8/18/2008 8:03 pm  
Blogger Peter said...

Can you turn on RSS for the site?

8/21/2008 8:49 am  
Blogger Vic Ferrari said...

http://feeds.feedburner.com/blogspot/oSBx

8/21/2008 4:21 pm  
Blogger Bank Shot said...

This is great stuff.

8/23/2008 8:38 am  

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