How FiveThirtyEight Is Forecasting The 2016 NCAA Tournament

Welcome to FiveThirtyEight’s forecasts of the men’s and women’s NCAA basketball tournaments. We’ve been issuing probabilistic March Madness forecasts in some form since 2011, when FiveThirtyEight was just a couple of us writing for The New York Times. While the basics of the system remain the same, we unveil a couple of new wrinkles each year.

Last season, we issued forecasts of the women’s tournament for the first time. Our big change for this year is that we won’t just be updating our forecasts at the end of each game — but also in real time. If a No. 2 seed is losing to a No. 15 seed, you’ll be able to see how that could affect the rest of the bracket, even before the game is over.

Live Win Probabilities

Our interactive graphic will include a dashboard that shows the score and time remaining in every game as it’s played, as well as the chance that each team will win that game. These probabilities are derived using logistic regression analysis, which lets us plug the current state of a game into a model to produce the probability that either team wins the game. Specifically, we used play-by-play data from the past five seasons of Division I NCAA basketball to fit a model that incorporates:

Time remaining in the gameScore differencePre-game win probabilitiesWhich team has possession, with a special adjustment if the team is shooting free throws.

These in-game win probabilities won’t account for everything. If a key player has fouled out of a game, for example, his or her team’s win probability is probably a bit lower than we’ve listed. There are also a few places where the model experiences momentary uncertainty: In the handful of seconds between the moment when a player is fouled and the free throws that follow, we use the team’s average free-throw percentage. Still, these probabilities ought to do a reasonably good job of showing which games are competitive and which are in the bag.

We built a separate in-game probability model for the women’s tournament that works in exactly the same way but uses historical women’s data. Thus, we’ll be updating our forecasts live for both the men’s and women’s tournament.

Elo Ratings

Otherwise, the methodology for our men’s forecasts is also largely the same as last year. But we’ve developed our own computer rating system — Elo — which we include along with the five computer rankings and two human rankings we used previously.

If you’ve follow FiveThirtyEight, you’ll know that we’re big fans of Elo ratings, which we’ve introduced for the NBA, the NFL and other sports. We’ve now applied them for men’s college basketball teams dating back to the 1950s, using game data from ESPN, www.sports-reference.com and other sources.

Our methodology for calculating these Elo ratings is highly similar to the one we use for NBA. They rely on relatively simple information — specifically, the final score, home court advantage, and the location of each game. (College basketball teams perform significantly worse when they travel a long distance to play a game.) They also account for a team’s conference — at the beginning of each season, a team’s Elo rating is regressed toward the mean of other schools in its conference — and whether the game was an NCAA tournament game. We’ve found that historically, there are actually fewer upsets in the NCAA tournament than you’d expect from the difference in teams’ Elo ratings, perhaps because the games are played under better and fairer conditions in the tournament than in the regular season. Our Elo ratings account for this, and also weight tournament games slightly higher than regular season ones.

Elo ratings for the 68 teams to qualify for the men’s tournament follow below.

RATINGSPROBABILITY OF…TEAMREGIONSEEDELOCOMPOSITEFINAL 4CHAMPSKansasSouth1209794.545.1%19.1%North CarolinaEast1207593.943.615.0VirginiaMidwest1205292.530.49.8Michigan StateMidwest2207891.833.98.9OklahomaWest2197290.032.06.8VillanovaSouth2204591.322.46.4KentuckyEast4201490.715.94.4West VirginiaEast3195689.316.23.4PurdueMidwest5193888.713.02.7OregonWest1203388.022.62.6Texas A&MWest3191586.812.42.4XavierEast2197387.79.91.8ArizonaSouth6195389.06.01.8DukeWest4191087.312.11.7MarylandSouth5187687.46.31.3IndianaEast5193887.45.81.1Miami (FL)South3193387.14.91.0Iowa StateMidwest4186786.56.41.0BaylorWest5183785.56.01.0TexasWest6178884.75.90.9UtahMidwest3188786.65.30.8Wichita StateSouth11189386.62.70.7CaliforniaSouth4187186.54.00.7IowaSouth7190485.93.20.6VanderbiltSouth11184685.62.40.5GonzagaMidwest11191686.03.20.5WisconsinEast7189684.82.90.4Notre DameEast6183284.42.60.3ConnecticutSouth9187285.32.10.3CincinnatiWest9179483.73.20.3ButlerMidwest9181584.22.50.3Seton HallMidwest6191484.51.80.2Virginia CommonwealthWest10179883.12.20.2DaytonMidwest7178882.41.60.1SyracuseMidwest10177282.71.30.1PittsburghEast10178782.31.20.1Saint Joseph’sWest8181481.61.10.1ProvidenceEast9182482.50.80.1Northern IowaWest11175180.20.8Stephen F. AustinEast14182481.00.4ColoradoSouth8175681.50.4YaleWest12179280.21.0Texas TechMidwest8177781.30.4TulsaEast11169079.90.2MichiganEast11176879.60.3Southern CaliforniaEast8173381.40.2Arkansas-Little RockMidwest12173478.90.2South Dakota StateSouth12173578.60.2TempleSouth10173078.50.2North Carolina-WilmingtonWest13172277.70.2Oregon StateWest7174077.60.2IonaMidwest13175978.20.1Green BayWest14166776.20.1Stony BrookEast13166377.10.1ChattanoogaEast12161076.6HawaiiSouth13173778.0Fresno StateMidwest14170876.6BuffaloSouth14161375.7Cal State BakersfieldWest15163575.00.1Middle TennesseeMidwest15163875.0North Carolina-AshevilleSouth15155374.2Weber StateEast15162373.3Florida Gulf CoastEast16154471.4SouthernWest16139268.0Austin PeaySouth16147768.8HamptonMidwest16148868.6Holy CrossWest16142066.9Fairleigh DickinsonEast16141766.72016 NCAA Tournament Team Ratings

Note, however, that Elo is still just one of six computer rankings that we use for the men’s tournament. The other five are ESPN’s BPI, Jeff Sagarin’s “predictor” ratings, Ken Pomeroy’s ratings, Joel Sokol’s LRMC ratings, and Sonny Moore’s computer power ratings. In addition, we use two human-generated rating systems: the selection committee’s 68-team “S-Curve”, and a composite of preseason ratings from coaches and media polls. The eight systems — six computer-generated, and two human-generated — are weighted equally in coming up with a team’s overall rating.

We’ve calculated Elo ratings for men’s teams only. For women’s ratings, we rely on the same composite of ratings systems that we used last year. You can find more about the methodology for our women’s forecasts