Two dudes blogging and podcasting about the San Jose Sharks, straight from sunny California.

post Book Report – Why NHL Teams Win at Home

February 26th, 2011, 7:39 pm

Filed under: blog — Written by Mike

I like reading sports books, and I like reading economics-type books.  Which is why I was interested to read Sportscasting: The Hidden Influences Behind How Sports Are Played and Games Are Won.  Worst case, they’d have some interesting theories about sports with scarce or anecdotal data to back it up (the way some people criticize Malcom Gladwell’s work) and best case it would really shed light on some interesting sports conundrums.  So which is it?

Actually, the latter.  And in order to achieve it, the authors crunched a ton (is it tonne in Canada?) of data.  It’s not nearly as breezy as a Gladwell read, but it’s meatier.  More tables, more numbers, more statistics, more explanations and hedges about what can properly be controlled for, and what can’t.  Those who have read this site for a while and listened to our podcasts know I love that kind of thing.   A couple of long chapters of the book are setting up the dominos to answer the question- why do home teams have such a big advantage?

There’s no doubt there IS an advantage, and it’s substantial in pretty much every sport.  Soccer is the most lopsided, with well over 60% of games being won by the home team (they calculated the numbers for MLS, EPL, Serie A, La Liga, and others).  Basketball is next, with the NBA home teams winning 62.7% (they even calculate WNBA and college).  The NHL is next, with 59% percent of home teams winning, and football (57.8%) and baseball (54.1%) bringing up the rear.

So, some things that are interesting about this discussion, the first being obvious, the others not (but backed up by the data).

  1. Home teams win the majority of games, sometimes a significant majority.
  2. This winning percentage is constant across time.  The winning percentage of home teams was about the same 50 years ago as it was 10 years ago, or now.
  3. The winning percentage is directly related to the sport itself.  Japanese baseball home teams have about the same winning percentage as MLB home teams.  Arena football the same as the NFL.

I’ve never thought about this too much before, but even #1 is really remarkable.  Why do home teams win so much, and so consistently?  There has been no NHL season where away teams won more games than home teams. As watchers of plenty of NHL games, I’m sure we all think of several reasons why this is.  One is the home crowds- the home players play better when you’re cheering them rather than booing them.  Another is travel- away teams have to deal with hotels, unfamiliar surroundings, and jetlag.

Incredibly, the authors make very good cases that both of these are myths.  It’s really hard to control for home crowds, because there are so many other interactions going on.  But here’s one feat in hockey that’s essentially isolated from all those player and referee interactions- the shootout.  It’s basically an interaction between two players and the crowd.  So if the crowd were a factor in home player’s effort and performance, you expect the shootout to have a home-rink advantage the way the rest of the game does, right?  Well, it doesn’t.  Since the shootout started, away teams won the shootout 50.6% of the time.  The home-rink advantage just doesn’t exist in the shootout.

And, amazing, they manage to control for travel as well.  How could you do that? Well, what about teams that are really close together, like the Devils, Rangers, and Islanders?  You’d expect less home advantage when those teams play each other, because they don’t have to really go anywhere- just drive a bit further.  But if you look at those games, the home advantage is exactly the same as all the other games.  They found there is a small effect with back-to-back games, which in most sports occur more often on the road.  But that’s not nearly enough to explain it all.

So what the hell is it?  I’m going to put a break here in the post, because some people might actually want to read the book and not get the spoiler.  I’ve condensed many pages into this post, and believe me, it’s worthwhile to read all the other support the authors have come up with.  Or, more likely, you just want to bail out because there’s too many words reading sux zzzzz…..