Here is on of my few posts on sports. Right now is “March Madness”, and millions of people all over the country are scrambling to fill in their brackets and predict the winners of the 63 games that make up the NCAA Tournament. (Actually it’s 67 games, but never mind that.) Various strategies are on the table. There’s the strategy of picking winners by their mascots: large animals beat small animals, humans beat animals, armed humans beat unarmed, and so forth. Then there’s the strategy of choosing teams based on their time zone: teams from the Eastern Time Zone will have more time to rest up when they travel west, while those traveling west to east will be short on sleep. I, on the other hand, have a strategy that actually works.
The strategy is this: pick the higher-seeded team in every game. In other words, don’t predict any upsets. Thus the only real choices you have to make are in the Final Four, since you’ll predict all the #1 seeds to reach it.
“Wait!” I hear someone crying. “That doesn’t make sense! There are always upsets, so if you want to win the pool, you have to predict upsets.” Not so. That reasoning is based on a misunderstanding of probability.
Consider a piece of advice I read on a website last year. On average, one 11th seed defeats a 6th seed in the opening round each year. (There are four games pitting 11th seeds against 6th seeds.) Thus, this hapless website advises readers to pick one upset in which and 11th seed defeats a 6th seed.
That advice is flawed, though, because you don’t know ahead of time which 11th seed will pull off the upset. The odds are against a victory by any one particular 11th seed, even if they’re in favor of one of the four pulling off the upset. It’s an exercise in basic probability theory to show that your expected returns are better if you wager on all the 6th seeds emerging victorious.
The same logic applies to the tournament at large. While there will certainly be some upsets, you can’t know ahead of time which possible upsets will occur, so you don’t benefit from predicting upsets. Predicting the higher seed every time and the odds will be in your favor. That’s my advice, in any case. If you choose to pick by mascot, don’t blame me for the results.