How Science Can Help You Win Your March Madness Pool

Kentucky forward Julius Randle shoots over Florida forward Will Yeguete and Florida forward Casey Prather during the first half of an NCAA college basketball game in the Championship, March 16, 2014. Image: John Bazemore/ AP Photos

March Madness is finally here, and I am putting aside a lot of work to focus on what’s really important: My office pool bracket.

For each of the past four years, I’ve outlined a way to use a little math to maximize the value of your picks in an NCAA men’s basketball tournament pool. Here’s this year’s update, with some new numbers and a little new thinking.

The big news in bracket pools this year is the $1 billion prize that Yahoo is offering (insured by Warren Buffett!) to anyone who picks a perfect bracket, nailing the result of all 63 games. Buffett likely won’t have to pay up–the odds of picking a perfect bracket are, according to our friends at FiveThirtyEight.com, somewhere around 1 in 128 billion.

What you can do is try to optimize your chances of winning the pool you’re entering. To do that, you’ll need to look for teams that others in your pool are over- or under-valuing.

Generally, most people’s picks in tournament pools look pretty similar. After a while, you see a consensus. For instance, the millions of people in ESPN’s online pool almost universally believe the top four seeds will win their first game (they’re almost certainly right, as a top seed has never lost to a 16 seed in the first round).

But you can look at each round, and each game, and see the percentage of players who’ve picked which winner. Call it the wisdom of the crowd, which is pretty darn good. Even with the unpredictability of the tournament, the crowd’s consensus picks usually finish in the 80th percentile or so.

But if you run with the crowd, it’s hard to beat them. Here’s a different way to look at things:

Here’s what those numbers mean. They’re the difference between the crowd’s pick at ESPN, and the statistical prediction of top college basketball analyst Ken Pomeroy and the team at FiveThirtyEight.com.

I’ve compared the average of those statistical projections with the ESPN percentages. A positive number means the stats say a team is more likely to win than the crowd thinks; negative means the stats say they’re more likely to lose than the crowd thinks.

Games that have more than a 10 percent difference are highlighted—green showing teams that are good bets compared to the crowd and red showing bad bets.

The biggest thing that stands out? The crowd has massively over-valued the Florida Gators. (Interestingly, the Gators were under-valued by the crowd last year). The stats guys have them in what is essentially a three-way tie (with Arizona and Louisville) as the team most likely to win the national title, yet a massive 27 percent of ESPN users have picked them to win. That’s about 14 percent more than one would expect. If you pick Florida to win, you’ll have a lot of company in your pool. Arizona is the best value pick as the National Champ at this point.

Also, look at the first round games. Part of the thrill of the tournament are the early round upsets, but the crowd isn’t picking a lot of them at the moment. Teams that the stats argue have a fighting chance of pulling off an upset–Harvard, Providence, Dayton, New Mexico State–are significantly under-valued by the crowd. Of those, I’d say that Harvard and Providence are the most under-valued, as they are the only two teams in the field to be undervalued by more than 10 percent in both the first and second rounds.

Of course, this is a high-risk, high-reward strategy. Brad Null, who runs a site called Bracket Voodoo that will analyze your bracket for you, notes: “Determining over and under-picked teams versus win probability is a good foundation upon which to start constructing your bracket, but you also need to account for a few other factors, such as how big your pool is and your scoring system. In a really small pool, it may still make sense to stick with one of the favorites like Arizona or Louisville. In a larger pool, you will probably have to dig a little deeper to find the right gambit, which could involve picking a different champion, like Virginia or Villanova.”

Best of luck to you all. If you’re looking for the full set of data, you can find it on Google Docs. Now if you’ll excuse me, I have to complete my bracket…