In the long, drawn-out days between Selection Sunday and the beginning of the round of 64, college basketball fans have two pastimes: filling out their brackets and complaining about the NCAA Tournament selection committee’s decisions.
This year was especially ripe for the latter, with grievances coming in from all corners of the college basketball universe. (Hint: When even the No. 1 overall seed — in this case, Kansas — has room for complaint, the committee might not have done its best work.) But how much does this stuff really matter? Can small changes to the committee’s decisions make a big difference to a team’s odds of going deep in the tourney?
To figure this out, we used the same method that drives our March Madness predictions and randomized the bracket around the committee’s S-curve rankings — the actual 1-68 ranking of teams the committee uses to guide the seedings and overall placement of teams in the bracket. Because the committee doesn’t adhere strictly to the S-curve within each “seed line” — it has the leeway to place teams according to factors (like geography) that go beyond balancing each region’s strength — we can judge how much the committee’s decisions at the margins affected each team’s chances of advancing to various rounds. And because we’re keeping teams in the same S-curve slots as the committee’s, we can examine these differences without delving into alternate universe-type scenarios in which the crusty old voters valued the teams differently.
Here are the teams whose odds to get to the Sweet 16 and Final Four were helped and hurt the most.
As far as the championship is concerned, these tweaks don’t matter much; most teams’ odds of winning it all were affected by less than a percentage point. But in terms of advancing to prestige benchmarks like the Sweet 16 and Final Four, the draw can have a relatively large effect. By being in a favorable region, for instance, Oklahoma’s Final Four odds were boosted by 12.1 percentage points, while Villanova was dinged by 4.4 points because it was dropped into the same region with Kansas.
And that’s just looking at the committee’s deviations from its own S-curve. What if the crusty old voters did value the teams (slightly) differently? In another simulation, we randomized the S-curve itself, giving a team the potential to move up or drop down into the top or bottom half of the next “seed line.” For instance, a No. 3 seed could have moved up into one of the bottom two slots on the S-curve for No. 2 seeds or just as easily dropped into one of the top two slots for No. 4 seeds. For each of those random draws, we simulated the bracket and then tracked how much each team’s odds changed in their most and least favorable draws.
Here are the results when we model the S-curve this way:
For top teams, the difference between its 20th- and 80th-percentile draw was 10 to 15 percentage points of Final Four probability, all due to the whims of its position on the S-curve.
Certainly, there are more factors determining how far a team goes in the NCAA Tournament than simply its starting point in the bracket. But in a wide-open field in which every edge counts, even small shifts in probability can add up.
Check out FiveThirtyEight’s 2016 March Madness Predictions.
Our sports podcast Hot Takedown previews March Madness.