Correlation Between Seed Number and Making the NCAA Women's Sweet Sixteen

The brackets have been announced for this year's women's NCAA Division I championships. A couple of matches will be played Thursday, but most of the action in the 64-team field gets underway Friday. At each of this weekend's sites, the second round will be played the night after the first-round matches. Tonight, and during the next three weeks, VolleyMetrics will be exploring various statistical aspects of the NCAA's "December Madness."

Tonight, let's start with something very basic, namely the record of No. 1-through-No. 16-seeded teams over the past five tournaments (2003-2007) in making the Sweet Sixteen. That is, of course, the immediate goal of all teams playing this weekend. Unlike the NCAA basketball brackets in which all 64 teams are seeded (i.e., each of the four regions has its teams seeded 1-16), the women's volleyball bracket only seeds 16 teams (explicitly) total.

Thus, for example, among the 16 teams vying to make the four-team regional to be hosted by Penn State, one can see teams labeled with the No. 1, 8, 9, and 16 seeds nationally, and the remaining 12 teams have no seed number by their names. Each of the other three regions also has four seeded teams. The NCAA committee may well, of course, have ranked all 64 teams so that the No. 1 seed gets easier early-round opposition than does, say, the No. 16 seed, but such rankings are not shown explicitly in the brackets released publicly.

At this point, it should be mentioned that all of the 16 explicitly seeded teams are expected to make the "Sweet Sixteen" (i.e., the four four-team regionals). But do things actually work out that way? As stated above, I have examined the past five years' tournaments to look at whether highly seeded teams have a better track record of making the Sweet Sixteen (regionals) than do lower seeds, among the 16 seeded teams. To increase the sample sizes and thus reduce chance fluctuation, I have grouped together the No. 1-through-4 seeds, 5-8 seeds, 9-12 seeds, and 13-16 seeds. Here are the results...

Teams seeded No. 1-4 are a perfect 20-of-20 in making the Sweet Sixteen during the past five years.

Teams seeded 5-8 have had a little bit of turbulence, successfully making the Sweet Sixteen 17-of-20 times (85%). Two of the exceptions occurred a year ago, with No. 6 Washington losing in the second round (round of 32) to BYU, and No. 7 Wisconsin losing in the same round to Iowa St. In 2005, it was No. 5 Stanford losing in the second round to Santa Clara.

Likewise, teams seeded 9-12 have had a 17-of-20 success rate. Last year's wacky brackets also saw the premature exits of No. 9 Kansas St. (to Oregon in the second round) and No. 11 Hawaii (to Middle Tennessee in the second round). The third upset involved No. 12 USC losing to Pepperdine in 2005, again in the second round.

Finally, as might be expected, teams seeded 13-16 have the lowest success rate of making the regionals, 14-of-20 (70%). I won't bother to list all six of the upset losers.

Interestingly, only one year of the last five, 2003, has seen all 16 national seeds move on to the Sweet Sixteen. In 2006, 15 of the 16 did. It thus seems likely that at least one of this year's 16 national seeds will be gone by this weekend. Whether things will be as wild as last year, when six of the 16 seeds failed to make it to regionals, remains to be seen.