Home, Sheet Home: Is Olympic Ice Really an Advantage?

by P.A. Jensen/Special to CHN

College hockey has no standard rink size. Most Division-I men’s teams play on an NHL-size sheet of ice (85 feet wide), but several play on Olympic sheets, which are wider (100 feet). Some even play on “hybrid” ice that is somewhere in the middle. This variety adds a unique element of home-ice advantage to the college game.

Or does it?

According to conventional wisdom, teams with big sheets of ice recruit players to fit a wide-open style of play, giving them a unique edge at home. Coupled with the fact that most schools rarely play on Olympic ice, this creates what might be called the “big-ice advantage,” at least in theory.

In practice? Not so much.

Nine teams currently play on home ice that is at or near Olympic-size: Alaska, Alaska-Anchorage, Colorado College, Massachusetts, Minnesota, New Hampshire, Northern Michigan, St. Cloud and Wisconsin (and, until the 2013-14 season, Minnesota State). If these “big-ice” teams enjoy a distinct home advantage over the other 50 teams in Division I hockey, that advantage should appear in their home winning percentages.

It doesn’t.

Over the past 10 regular seasons, D-I teams’ average home winning percentage is 55.2 percent (excluding non-D-I opponents and formal “neutral-site” games). This five-point advantage over a neutral 50% is statistically significant, and strongly so (p~0). In general, a five-percent swing like this would manifest as about one win per 20 home games, or just under one extra home win per year for each team.

This average is almost identical to the average home winning percentage of small-ice schools (55.3%), which makes sense, as they make up the bulk of Division I programs. The average home winning percentage among big-ice programs, however, is no higher. It is 54.6% — less than a point below small-ice schools, but statistically indistinguishable from them. So, programs with big sheets do not win more games at home, at least in absolute numbers.

Of course, this does not account for the quality of the teams generally: maybe there is an advantage to having a big sheet, but the big-sheet teams aren’t very good, so their winning percentages are lower on average. This possibility can be addressed by comparing teams’ home winning percentages to their winning percentages on the road. If there is a “big-ice advantage,” schools with big sheets might have especially good home records compared to their away records. Said another way, they would have bigger differences between their home and away records, regardless how good their overall records are.

The difference between home and away winning percentages is not significantly larger for big-ice schools compared to small-ice schools. It is trivially larger: over the past decade, big-ice teams’ winning percentages jump 13.1% at home versus on the road, compared to 11.1% for other schools. However, this difference would amount only to about an extra tie per year, and it is not statistically significant (though it is close: p=0.12 by one-tailed t-test). Again, it appears that the big sheet gives no significant advantage, but even if the difference were real, it would be quite small.

Graphing the home and away winning percentages of each school also shows that there is no significant “big-ice advantage.” Each dot in the graph represents a school, and is positioned according to home and away winning percentages over the past decade. As one would expect, home and away winning percentages are positively correlated—as one increases, so does the other—and tightly so (R2=0.79, p~0). However, whether a school has a big sheet is not a significant factor in the correlation (or, the linear correlation, at least; p=0.31). On the graph, this means that compared to nearby white dots, black dots are not consistently higher.

So, what, all of this talk about Olympic ice is a myth? Hockey people, including head coaches of Division I programs, are making this up?

That’s hard to say. Players, coaches, and fans know that playing on “big ice” is indeed an adjustment, but the numbers suggest that the adjustment does not affect wins and losses, at least significantly. Also, maybe small-ice teams have learned to practice in a way that negates the effect of big ice, or maybe big-ice teams have to undergo similar adjustments when they visit small ice, which cancels their own home advantage. Again, it’s hard to say.

More bluntly, though, if there is some sort of “big-ice advantage,” it must be trivial, because it can’t be detected very easily.

So, the next time you hear fans or coaches talk about “big ice,” gauge what they’re saying. If they’re saying that the players will have to work to adjust their angles in practice, then sure, they probably have a point. If they’re talking about a sheet of ice as if it can magically change the outcome of the game, then pay no attention. That magical sheet of ice, Olympic or otherwise, doesn’t exist — they’re probably making that sheet up.

P. A. Jensen is editor of RuralityCheck.com.