Tuesday, August 12, 2008

Home Ice Advantage

We all know that teams have a better chance of winning at home than on the road, it's been that way since Bob Cole wore short pants. The question is: Why?

I've always believed that with hockey, it is more about rest and preparation time than anything else. Which is why I think Lowe had a valid point a few years ago when he criticized the Oilers business operations people for scheduling a whack of back-to-back games on home ice. The Oilers were trying to cash in on the weekends, and the higher concession sales and increase in out-of-towners that they bring. Fair enough, but when the Oilers miss the playoffs by a point or two, as they had that season, it seems less clever.

So a look at why home ice teams did better last season. This is just for even strength play for now, and doesn't include empty-net or shootout stuff. Hopefully somebody digs up the PP stuff one day and sorts through it. Any road, here you go, just click on the image to enlarge it:

I'll leave you to do your own arithmetic, but of the +198 in goals by the home teams, I make +45 as a result of better shooting%/save%, and the remaining +153 in goals from having more shots on net. And the underlying numbers, that ones that point towards puck possession, they are strong in about the right measure.

Obviously teams that have the pill more will usually end up getting more chances on the PP, even with Ethan Moreau's random head punching considered. Still, that seems a little steep to me, maybe the refs are getting swayed by the home crowd a bit. If you know of a site that shows 50n3 PP opportunities, or ice time, in home and away breakdowns, please leave a link in the comments. It wouldn't surprise me if the home squad is getting the benefit of those as well.

There are surely other things at play that haven't crossed my mind yet, and it's just one 1230 game season that I've looked at here. Still, a starting point.

16 Comments:

Blogger Jonathan said...

...it really looks like three quarters of the benefit is simply coming from having more puck possession.

So, fun question - what causes that? Last change is undoubtedly a factor, but do you think it's a factor to that degree?

8/12/2008 1:25 pm  
Blogger Vic Ferrari said...

I think that it's mostly just rest, preparation time too probably. Having the advantage of last stick down in the faceoff circle is apparently an advantage too, though I've never seen a site that breaks down home/away faceoff wins.

Mostly I just think that variances in the percentage numbers from week to week or month to month or from home to away ... I think that's just the clattering of dice. I'm not totally convinced of that, but it's the way I lean.

8/12/2008 2:28 pm  
Blogger Allan said...

I'd expect the biggest factor is the home team having the last line change.

It allows the home coach to hide his weaker players, and to exploit the other team's weaker lines, which provides an advantage on both sides of the ledger.

As an extreme example, see Joffrey Lupul's home/road splits in 06/07.

8/12/2008 3:55 pm  
Blogger Showerhead said...

Hmmm. Is it fair to take 153/30... and decide that due to more shots, each team in the league benefits by roughly 5 ES goals per season over the course of their 41 home games and suffers roughly 5 ES goals against per season in their 41 away games?

If you took every score that happens over the course of an NHL season and found an average difference between the amount of goals the winning team scores vs the losing team, would it be more or less than 1? Would these 5 ES goals be worth more or less than 5 wins?

---

Also, if it's ok to take my suggestion of 5 ES goals over home games at face value (correct me if I'm wrong) then I disagree with your assertion that this difference comes from preparation and rest.

Preparation - what is the average amount of time between games on the road vs. at home? Significant enough to add up to .2 ES goals per game on the basis of strategy and prepwork? I would suggest that the majority of goals attributable to these would come on special teams and wouldn't factor in here.

Rest - I'm sure it has some effect, but can you quantify it? What about being at home with your family or being able to go out on the town because it's your city? Can you quantify those? While these factors surely exist, I don't think they combine to be that significant... and until someone can tie them directly to goals for/against, they're too fluffy for my tastes.

Instead, I'll go with line changes. Think back to the beginning of Pronger's season when we had Crossanov as our bottom pairing. If Edmonton plays 41 games at the Saddledome, what are the odds that Sutter can get +5ES goals out of Iginla by throwing him over the boards at the right time? Anecdotally, line mismatches are a whole lot more believable to me than prep time.

8/12/2008 5:04 pm  
Blogger Slipper said...

The short change must factor into this, no? Besides the obvious changing for fresh legs and being closer to the defensive zone.

A coach has the advantage of manipulating the match-ups in transition because his forwards have the closer bench. Ecspecially if the other team's forwards are pressing deep before the puck turns over and/or are caught on the far side of the ice. There are probably alot of minute advantages both going forward and coming back, if one was to brainstorm.

It would also be interesting to see if the position of the bench affects the number of dump-ins a team exercises during a game on home ice versus on the road, and if the difference was signifigant at all.

8/12/2008 10:21 pm  
Blogger Jonathan said...

The short change must factor into this, no? Besides the obvious changing for fresh legs and being closer to the defensive zone.

This should be easy to check - if that's the case, than the second period in road games would look like the first and third in home games, and the second period in home games should be noticeably inferior to the 1st and 3rd.

8/13/2008 8:57 am  
Blogger Matt said...

Since home advantage is in no way unique to hockey, I think you have to give at least some of it to that fuzzy concept of "greater adrenaline/pride/etc." playing in front of the home fans, friends & family, what have you.

In basketball (e.g.) there is zero structural advantage to being the home team, but it's an even bigger advantage than in hockey. In football, basically the same: the home crowd can disrupt the visiting offense's communication, but that barely goes partway to explaining the pretty significant advantage the home team has.

8/13/2008 11:07 am  
Blogger choppystride said...

I think rest must be a pretty huge factor. I mean, every once in a while, you would hear about how a road team rushes to the airport right after a game and then doesn't get to the hotel in the destination city til 3am. That's got to take a toll on the body.

I wonder if this effect would have less of an impact on playoff data.

8/13/2008 11:26 am  
Blogger Vic Ferrari said...

Terrific comments all around, good stuff.

choppystride/Matt:
While I agree with both of you, probably more with CS, intuitively, the point choppystride brings up about playoffs really enforces Matt's take, the oddsmakers always weigh the home team heavier in the playoffs, especially in intense buildings. They like the adrenaline factor.

SJ vs EDM in 05/06 and SJ vs CGY last season are probably the best examples of this, off the top of my head.

8/13/2008 12:34 pm  
Blogger Vic Ferrari said...

slipper:

I hadn't thought of that, though having the short shift going forward helps the other way too. Still, as you say, obviously having the short shift on your defensive side is a bigger advantage, otherwise home teams would switch the benches up.

To my mind, Hitchcock is the king of the short change, granted I don't watch a lot of the east, and there are a bunch of newer coaches in this league that i don't have a really solid feel for. Still, that would be a place to look, hopefully one of us does eventually.

Having said that, jonathon's suggestion is undoubtedly better than mine. That's commonsensical shit.

8/13/2008 12:38 pm  
Blogger Vic Ferrari said...

allan/showerhead:

I'm sure it's a factor to some extent, how much is harder to say. I mean being at home gives you first dibs only, not every matchup.

So you can be sure that when DET roll into STL next year, Andy Murray (who never runs power-vs-power), he'll have first choice, and undoubted his first choice will be "I don't want Kariya/Tkachuk playing against Zetterberg", and you're not going to get a Mexican standoff with these two like you would with Crawford/Tippet/Carlyle/Hitchcock and the other hardcore matchers, Babcock will still play the Z line, accept the match that Murray wants (probably that poor Stempniak fucker, Oilers should run at him when he becomes UFA imo, that's a good player who is going to have bad numbers) and take Lidstrom/Rafalski vs Tkachuk/Kariya and whoever is fit and on form of the rest of the forwards (Draper and Cleary are good bets here I think).

Book that, seriously. I've been wrong enough that I'm not bothered if I'm wrong again. But leopards rarely change their spots, and Babcock is Babcock and Murray is Murray, bless 'em both.

8/13/2008 12:50 pm  
Blogger Vic Ferrari said...

One thing I'd like to add, hell it was a big part of the reason I posted, is that possession seems to be a big part of home ice advantage, in fact most of it. Can we agree on that?

If so, we can look at the stuff that usually gets murdered by sample size. Home back-to-backs vs road back-to-backs, for example.

8/13/2008 12:55 pm  
Blogger Vic Ferrari said...

Damn, growing old is a bitch.

I don't worry about typos, but my there/theirs have been a mess for a while now. And now I'm mixing up accept/except the minute that my head gets ahead of my fingers. It's just sad.

Take mercy on me, grammar Nazis.

8/13/2008 4:05 pm  
Blogger Jonathan said...

One thing I'd like to add, hell it was a big part of the reason I posted, is that possession seems to be a big part of home ice advantage, in fact most of it. Can we agree on that?

Well, I think it's pretty clear that having 2000 more shots is more important than having a 0.1% advantage when shooting, so yes.

Still, what causes the possession advantage- something like rest may be a factor, but you'd think it would show up on the shooting/save percentage end of things to, wouldn't you? Whereas things like having the short change and the last change would tend to show up more in the various possession metrics, yes?

8/13/2008 4:44 pm  
Blogger Kent W. said...

probably that poor Stempniak fucker, Oilers should run at him when he becomes UFA imo, that's a good player who is going to have bad numbers

Off topic, but thank you for confirming my suspicions. I chose Stempers in a couple pools last year and he just sank. I watched a couple of Blues games and see Murray is playing him with McClement and Backes as a checking unit! He got PP time, but...why the hell would you a coach do that to one of the team's top goal scorers from the last couple seasons?

8/13/2008 6:19 pm  
Blogger Doogie2K said...

Since home advantage is in no way unique to hockey, I think you have to give at least some of it to that fuzzy concept of "greater adrenaline/pride/etc." playing in front of the home fans, friends & family, what have you.

Exactly. And mental preparation, focus, and particularly fatigue (as it affects the first two) also have to be considered here, too. Longer trips like, say, Edmonton to Dallas, can wear you the hell out at the best of times, and especially when you're leaving arenas at 11 PM and hitting the hay closer to 2 or 3 AM, as was noted above, and I have to think that over the course of a season, that can manifest itself occasionally.

Incidentally, all the naysayers of "fluffy" or "fuzzy" things like this really should try taking a sports psychology course or two. The fact that it's hard to quantify doesn't invalidate it in the slightest.

8/14/2008 6:30 pm  

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