North Carolina-Boston College: Don't Act So Surprised

Andrew KahnCorrespondent IJanuary 5, 2009

Previously unbeaten No. 1 North Carolina lost to Boston College last night, but I wasn't surprised.

All right, I suppose that's not entirely true.

That the most dominant team in the country lost to an unranked opponent, at home, in the conference opener, was a bit of a shocker. But the laws of probability tell us that even a great team like Carolina going undefeated too far into the season is unlikely.

When you do some math, you realize how absurd an undefeated season really is.

Let's take a look.

UNC had played 13 games before losing. Two of those games didn't have a spread, but in the 11 that did, UNC was favored by at least 17.5 points in nine of them. The Tar Heels were only a ten-point favorite against both Notre Dame and Michigan State. They won the latter contest by 35.

It's safe to assume that barring injuries, UNC will be favored in every game this season. Of course, that doesn't mean all that much, since they were 22.5-point favorites against BC. But for the sake of this "experiment," let's say UNC has a 90 percent chance of winning each game.

While some games (Chaminade, Oral Roberts, etc.) the Heels arguably have a greater chance of winning, others, at least in the minds of the experts, they have a much less chance of winning. I don't believe 90 percent is a fair number — I think it's too high. But that will only help illustrate my point.

If the Heels have a 90 percent chance of winning each game, the odds of them winning even seven in a row is less than 50 percent (.9 to the seventh power equals .48). To get to 10-0? That's a 35 percent chance. Achieving the 13-0 mark Carolina reached before losing yesterday? 25 percent chance.

This is why the talk of an undefeated season was so ridiculous. Using the same math, a team only has a four percent chance of going 30-0. Even after increasing UNC's chance of winning each game to 95 percent, we see it still only has a 21% chance of going 30-0.

Do you really think that Duke only has a five percent chance of beating Carolina at Cameron?

As for why the Heels lost this particular game, perhaps we really shouldn't be surprised. The factors that make you think they should win — at home, lower-tier conference opponent — may have worked against Carolina.

Whenever the No. 1 team goes on the road, the energy in the building is unparalleled. Fans fill the arena hoping to see an upset, while the opposition plays with an extra adrenaline boost. At home, unless it's a rivalry game, the fans aren't particularly excited. They get to see the No. 1 team all the time.

Last night, the crowd was likely even less rowdy as many students were not in attendance. Classes don't start at UNC until January 12. Perhaps the players, like the fans, simply expected to win. Shooting 29 percent in the second half certainly didn't help either.

In every game this season, UNC is going to be the better team, so regardless of who they lost to it would have been considered an upset. While the experts continued — and likely will continue — to make Carolina a heavy favorite, it didn't mean they thought the Heels were going to run the table.

It just meant they didn't know which game they were going to lose. As long as you believe Carolina has better than a 50 percent chance of winning any given game, you can't make them an underdog. But you can be sure that the odds for any prop bets regarding an undefeated season were against the Heels doing so.

It's simple math.