This season, playing at home isn't worth as much as you might think.
Note: The following is taken from Nick Christenson's weekly CFL analysis (Week 10). We think this data deserves special attention.
Let’s take a look at home field advantage in the CFL so far this year. It’s pretty easy to calculate. One takes the sum of all points scored by the home teams, subtracts the sum of all points scored by the visiting teams, and then divide this difference by the total number of games played.
So, if we do that for all the games so far this year, including the games played so far this week, we get a cumulative home field advantage in the CFL of 0.8 points per game. That’s pretty low. And, if we only count games that occurred before this week, it would actually be just slightly negative.
The master caveat that applies to all football math, especially in the CFL, must be invoked here. Thirty seven games is way too small a sample size from which to draw conclusions. Heck, HFA has gone up by almost a point after just three games this week.
Historically, CFL home field advantage has averaged about 3 points per game over the last two decades. Some years the math above has produced numbers that have been at or near zero or even negative over the course of a season. Does that mean that the home field advantage was really zero during that time? Probably not. In most, if not all, cases, outlier values will have been random fluctuations, and even during these periods, HFA was probably close to its long term average.
Is it possible that there is some reason home field would not be as valuable this year as it has been? Perhaps, but I don’t know what that reason would be. While crowds aren’t at capacity this year, there are still crowds, and I’d expect travel is, if anything, more difficult this year with the COVID restrictions in place than it has been in years past. So, why would traveling teams have an easier time of things this year than before? I can’t think of a good answer.
So, my assumption is that the long term trend is more reliable than what games so far this year would indicate, but it’s something to keep an eye on. At the very least, before making bets we might want to ask ourselves if we’d still like the bet if HFA were actually lower this year than its historical average.