Home Ice (Dis)Advantage?

Now that the playoffs are well underway, we at VFMS pondered a very big question: is home ice really an advantage?  So, being the analytical statistics person, I tackled this big question.  First, I compiled all of the results from every playoff game from 2005-2010.  The next step involved extracting all sorts of data from this information to try to get at the crux of the question.  This was a giant task, and was done with a great deal of help from Micah Sussman, author of What’s in a Name??, a fun blog about the history behind team names.

It’s important to understand how specific terminology is used throughout this article.  Whenever I refer to a home team or an away team, it strictly means the team playing at home or away in a specific game, and has no bearing on which team has “home ice advantage” for a series.  If I am referring to home ice advantage, I will state that in the text.

The first, and most obvious question is: which team wins more games in the playoffs – the home team or the away team? While this seems obvious, the stats may surprise you – the home team does win more games. However, in the past 5 years, 425 playoff games have been played, and the home team only won 233 (54.8%) of them (Table 1).  While this margin is statistically significant, I was surprised to see that the away team still managed to win 45.2% of games.  Interestingly, if you look at how many goals are scored by the home and away teams, the home team also had a slight advantage, scoring 1220 (52.3%) of the goals as compared to 1114 (47.7%) goals for the away teams (Table 2). Again, the difference in scoring is a smaller margin than I would have expected. This means that each game really is up for grabs by any team, but doesn’t really address the intricacies of a playoff match up.

Table 1. Outcomes of Home Games

Table 2.  Goals Scored During the Playoffs

 In the NHL playoff match ups, with a best-of-7 series, several games take on greater importance. When a team is facing elimination, they have one option – win, or hit the golf course.  When a game could result in the elimination of a team from the playoffs, the away team won 55.0% of the games.  However, this doesn’t take into account which team was facing elimination.  When a team faced elimination at home, the visiting team won 59.2% of games – eliminating their opponent on home ice (this includes the last three Stanley Cup final match ups).  Interestingly, when a team faced elimination away from home, they were just as likely to win (and avoid elimination) or to lose.

When it comes to winning a series, the away team won a striking 61.3% of games. However, this doesn’t take into account series where one team was swept by the other. A series sweep has occurred 10 times in the past 5 years (16.7% of series), with every team ending the series away (Table 3).  This may not be surprising, as this means the higher seed (which had “home ice advantage”) swept the lower seed in all 10 instances.  If we remove series sweeps from the calculation, the away team still won more games (55.4%), but the difference is far less dramatic.

When a series went to 5 games, which happened 22 times (36.7% of series), the home team won 54.5% of games (12/22) (Table 3).  However, this also means that the away team won 45.5% of games, meaning that the home team only had a slight advantage in these cases. However, given the nature of series that only extend to 5 games, the away team in those cases would, by definition, already have a 3-1 series win going into Game 5.

For those series extending to 6 games, which occurred in 25 (41.7%) of the playoff series, the away team won 64.0% of the time to take the series.  Intuitively, Game 6 is played at the arena of the lower seed, meaning the team with “home ice advantage” would be playing as the away team for Game 6. However, the margin of advantage is still not that great.

As we all know, many series go the full 7 games, coming down to a winner take all final game.  In the past 5 years, 18 different series have gone the distance (30.0%), and the winners were equally divided between home and away teams.  So basically, if a series goes to 7 games, the team with “home ice advantage” only wins half of those games (and series).

Table 3. Outcomes of Games that Clinched a Series Victory

After all that, what really remains is one simple question: is “home ice advantage” really an advantage? I think it’s fairly clear that, when examined globally, which arena hosts a game is not a reliable predictor of who is more likely to win the game.  In virtually every case I examined, the difference between playing at home or away results in outcomes that are similar to a coin toss, with one minor exception – if you’re going to lose a series, there’s a slightly better chance that you will do so at home, in front of your own, very disappointed fans.

Amanda Fortier