The Western Conference upset index

Jonathan Quick may have to stand on his head, but LA could topple the Canucks. Getty Images

The NHL postseason is a crazy time. While you rarely see a No. 8 seed beat a No. 1 seed in the NBA, it happens more often on ice. So -- if we look at previous upset models, what can we learn about the 2010 postseason pucks dance? That's what Puck Prospectus is out to explain. This article focuses on the Western Conference. You can find the Eastern Conference upset index here.

Let's say someone asked you to figure out the probability of a hockey upset in the playoffs based on the difference in points between two teams in the regular-season standings. You'd probably say that teams with the same number of standings points would each have a 50 percent shot at winning the series. As the gap in the standings increased between the teams, you'd give the underdog a smaller and smaller percentage change of winning. Makes sense, right?

It did to me as well, but when I started analyzing the results of every first-round series since 1980, I realized I was wrong. The odds of an upset actually stabilize at just under 40 percent, regardless of the size of that gap in the standings.

If the gap is between zero and four points, the probability of an upset is 37 percent. If it's between 20 and 24 points, that probability increases only a little -- to 39 percent. In short, the odds of a low seed pulling an upset are actually better than you'd assume.

Now, how does that apply to the 2010 playoffs?