Most of the focus when the N.C.A.A. tournament bracket is revealed on Sunday will be on how teams are seeded and what sort of opponents they’re due to face — and which teams make the field of 68 at all. But there is another factor that can make just as much difference: where the games are played.
Since 2003, for instance, teams playing an N.C.A.A. tournament game within 50 miles of their campus are a remarkable 24-2. One of the two losses came in last year’s championship game, when Butler — playing just miles from its campus in Indianapolis — came within 2 points of defeating a heavily favored Duke team.
By contrast, teams travelling at least 1,000 miles to play their game are 121-174, having won just 41 percent of the time.
Another way to look at these numbers: the team playing closer to home has won 59 percent of tournament games since 2003. When one team has to travel at least 500 miles more than the other, its advantage has been 67 percent. And when one team has been at least 1,000 miles closer to home than the other, it has been 73-25, winning nearly three-quarters of the time.
Savvy tournament-watchers might raise an objection to this: doesn’t the seeding committee tend to respect the geographic integrity of higher seeds more so than lower ones? If so, these numbers could be a function of differences in team quality rather than geography.
Since 2003, indeed, No. 1 seeds have had to travel an average of only 254 miles to play their first-round game — about the distance, say, from Lawrence, Kan., to Oklahoma City. No. 2 seeds have had to travel 285 miles.
Travel times increase sharply from there. No. 3 seeds often but not always stay close to home; they have to travel 583 miles, on average. No. 4 seeds, however, put an average of 868 miles on their odometers, no better than the lowly No. 13 seeds (855 miles) that they play in the opening game. (No. 16 seeds, ironically, fare better than this, travelling only 589 miles. The N.C.A.A.’s attitude seems to be that since these teams are almost certain to be eliminated after the first round, it might as well save on the air mileage.)
What happens after the first two rounds, when the tournament moves to regional sites and the seeding committee has less flexibility, gets more complicated. It’s increasingly important not only to be a No.1 seed, but also to be the overall No. 1 seed, a distinction that the tournament committee has made since 2004. (Ohio State is in the driver’s seat to get this designation this year). Not only will you theoretically be paired against a relatively weak No. 2 seed, but also, the tournament committee will almost always ensure that you play at the regional site closest to campus. By contrast, if there is an overload of No. 1 seeds from one part of the country, the “worst” one might get shipped out to the opposite coast.
These differences in the seeding committee’s habits do account for some of the geographic advantage that we observed earlier, but far from all it. Using a logistic regression procedure, we can estimate the likelihood that one team would beat any other based on their seeds (the formula is not completely linear: for instance, the difference between No. 1 and No. 2 seeds is generally quite a bit larger than the one between No. 4 and No. 5 seeds).
Based on their seeds, teams that are playing at least 1,500 miles closer to home should have won about 65 percent of these games since 2003. Instead, they’ve won 79 percent. Likewise, teams with a geographic advantage of between 1,000 and 1,500 miles should have won 61 percent of the time — but they’ve actually won 71 percent of the time.
It may be more intuitive to think of these differences in terms of point spreads. By projecting a margin of victory based on the seeding differentials and comparing it to actual tournament scores, we find that teams playing 1,500 or more miles closer to home beat expectations by about 5 points on average, while teams with an edge of between 1,000 and 1,500 miles do so by between 2 to 3 points. These differences are highly similar to the home court advantage in college basketball, which has been found to be worth about 4 points.
The actual procedure that we’ll be using to make our tournament projections is more sophisticated than this and is based primarily on computer power ratings rather than seeds. It also assumes that these geographic effects are not completely linear — for instance, there is a bigger difference between playing 50 miles from home and 250 miles than there is between travelling 2,050 miles and 2,250.
Our technique, essentially, is to assign a bonus or penalty to each team based on how far it has to travel. For example, a team that had to travel 1,500 miles would get a 1-point penalty, while a team playing just 100 miles from home would get about a 2-point bonus. In the most extreme possible case — a team playing literally on its home court (something which the N.C.A.A. does not allow) against one coming from the other corner of the country, this geographic difference could amount to as much as 6 points, but it will rarely be more than about 3 or 4 points — equivalent to having home court advantage during the regular season — in practice.
Even a couple of points, however, can make quite a bit if difference. I’ll be providing more detail about our model later, but it basically works by calculating a point spread and then estimating the underdog’s likelihood of pulling off the upset. For instance, if two teams were otherwise evenly matched but one had the equivalent of a 3-point advantage based on geography, it would win about 61 percent of the time rather than 50 percent.
Which teams should have the biggest geographic advantage this year? One candidate is Texas, which could fairly easily play its opening-round games in Tulsa, its regional in New Orleans, and the Final Four in Houston, all relatively quick trips from Austin. In one testing run that we did that involved this scenario, Texas’ chances of winning the tournament increased by about 50 percent — to roughly 6 percent from 4 percent — when we turned the geographic adjustment on.
The map is also worth watching for teams from the western part of the country, which usually have either a big geographic advantage or a long trip on their hands, with little room to split the difference. If Brigham Young is a No. 1 or No. 2 seed, for example, it will probably play its opening-round games in nearby Denver. But if it stumbles in its conference tournament and gets demoted to a No. 3 or a No. 4, it could find itself playing 1,900 miles away in Tampa instead.