Get inside March Madness with SI.com's Luke Winn in the Tourney Blog, a daily journal of college basketball commentary, on-site reporting and reader-driven discussions.
3/20/2007 11:16:00 AM
Pitting Odds Against Efficiency
The oddsmakers like Jo Noah's Gators more than the efficiency numbers do.
Chris Graythen/Getty Images
The SI tourney team re-assessed allfourregionalstoday in regular space, covering everything from clutch players, to X-Factors, to Final Four picks. (I was assigned East Rutherford and took Georgetown). That leaves the Blog free to examine the bracket from more esoteric angles.
For the second week in a row we have a guest contribution from Emory University student Jacob Wheatley-Schaller, who has added a new dimension to his odds-based analysis. In the chart below, Wheatley-Schaller has used futures odds from four online sportsbooks (bodog.com, betus.com, sportsbetting.com and vip.com) to calculate a "Vegas Percentage" -- the percent chance oddsmakers are giving teams to win the national title. He then compared those figures against Ken Pomeroy's efficiency-based percentages to see where bettors and stat-heads don't see eye-to-eye.
Four quick observations, followed by the full chart:
• Vegas' favorite teams are Florida, Kansas, UNC and Georgetown, in that order. The average percentages come out the same way. Seems like a bad sign for Ohio State. • Kenpom's favorites are Kansas, UNC, Florida, Ohio State, in that order. • According to the percentage gaps, Kenpom's numbers most differ with Vegas on the subjects of North Carolina (the efficiency-based percentage is 10.03 higher for the Heels) and Kansas (9.45 percent). • Conversely, Kenpom's percentages say that Florida (by 3.40 percent) Memphis (by 3.07 percent) are the most overrated in Vegas.
Odds vs. Efficiency
How Vegas, Kenpom Handicap the National Title Picture (arranged by region)
Vegas considers Jessie Sapp (left), Pat Ewing Jr. and the Hoyas to be the top No. 2 seed.
Jim McIsaac/Getty Images
In the Blog's ongoing efforts to attack this Bracket Math business from as many angles as possible -- efficiency profiles, as well as hotness "trendlines" have already been covered -- we're turning to the gamblers for Wednesday's post. Friend of the blog Jacob N. Wheatley-Schaller, a student at Emory University, used futures odds from four online sportsbooks to compute the percentage chances oddmakers are giving teams to win their regions. The chart appears below:
Las Vegas Percentages for Each Team to Win its Region
(Futures odds taken from bodog.com, betus.com, sportsbetting.com, and vip.com)
Jacob N. Wheatley-Schaller
If Vegas really is smarter than the rest of us at assessing teams, then here's what you should take away from Wheatley-Schaller's data:
• I consider Kansas-UCLA (in the West) to be the biggest 1-vs.-2 toss-up situation, and while the Jayhawks are the No. 1 with the lowest Vegas percentage, the smallest gap between a 1 and a 2 seed in the chart is in the East Region. There's only a 6.1-percent difference between UNC and Georgetown, and then a huge 20.5-percent drop between the Hoyas and Texas. There's a significant amount of bettor confidence in Georgetown.
• The oddsmakers really like Texas A&M's Final Four chances. The Aggies are by far the highest No. 3 seed -- 17.1 percent above Washington State, 11.7 percent above Pitt, and 10.3 percent above Oregon -- and also come in well ahead of South Region two-seed Memphis.
• Vegas' two biggest gaps in 8-9 games are Arizona (a No. 8 seed) over Purdue by 1.0 percent and Michigan State (a No. 9 seed) over Marquette by 0.9 percent. The other two 8-9s (BYU-Xavier and Kentucky-Villanova) are toss-ups.
Aaron Brooks and the third-seeded Ducks could be peaking at the right time.
Jonathan Ferrey/Getty Images
In the NCAA selection committee's bunker, the "hotness" of tourney squads is usually measured by the results of their last 10 games. There's a entire, pull-out section for "Last 10" on the committee's team sheets -- you can view it on the UCLA example Seth Davisposted last week -- that appears below the breakdown of a team's wins and losses against different tiers of the RPI. Regular fans, I think, use more arbitrary methods to take a team's temperature, such as gauging conference tournament performance -- or even more unscientifically, how good the team looked the last time you caught them on TV.
The Blog, in its ongoing obsession with efficiency-based analysis, is here to provide you with a new -- and improved -- way to identify the hottest teams heading into the NCAA tournament. I've enlisted the services of esteemed amateur stat-head David Hess, whose full previews can be found this week on HackTheBracket.com. Hess has been graphing Ken Pomeroy's game-by-game efficiency numbers for NCAA tourney teams, adjusting the data for home/road/neutral location and level of competition, and then applying what he calls "trendlines" -- curves that allow us to see whether a team is becoming more or less efficient leading into the dance.
Now for the juicy information: I asked Hess to pinpoint the hottest team in each region, based on the trendlines, and he delivered exclusive graphs to the Blog that appear below along with my commentary. (Note that an optimal team graph would have the top curve going UP, representing increased offensive improvement, and the lower curve going DOWN, representing increased defensive stinginess.)
The Midwest Region's hottest team:
The Ducks are even hotter than Florida, according to Hess' figures. Their offense has steadily improved over the course of the season -- a very promising sign -- and is at its peak level following a run through the Pac-10 tourney. Defense is not Oregon's strong point, but it has dipped down to a sub-90.0 rating (meaning it's giving up fewer than 0.9 points per possession) for the first time in months.
The West's hottest team:
This one should come as no surprise. The Jayhawks were consistently one of the nation's best defensive teams for the entire season, but have blossomed on offense over the past month. The only worry -- even though the figures are adjusted for competition -- is whether or not the Jayhawks' offense peaked against the weakest part of the Big 12 schedule, and is in for a reality check in the NCAA tournament.
The East's hottest team:
North Carolina and Georgetown, watch out. I put Mr. Durant and the 'Horns in the Final Four of my SI.com Writer Bracket for a reason. The most important thing in this graph is not the quality of Texas' offense, but the fact that its defense -- which has always been its weakness -- is finally hitting a respectable, sub-90.0 level. Finally, the South's hottest team:
Ohio State has been a high-quality team for months, but the school whose efficiency margin is peaking here is Louisville. The Cards' offense, even though it bottomed out in its Big East tournament loss to Pitt, has been hitting incredible levels down the stretch. I put Texas A&M in my title game, but this information, needless to say, has me worried about the Aggies' probable second-round matchup with the 'Ville in Lexington.
Acie Law, Joseph Jones and the Ags are better than your average No. 3 seed.
Ronald Martinez/Getty Images
As you pore over your bracket picks this week, can you distinguish between the important factors and the irrelevant ones? You'll undoubtedly agonize over things such as, whether Texas A&M's home-court advantage in San Antonio will help the Aggies knock off Ohio State (yes); if UCLA's season-ending choke job should be considered a distress signal (not really); and how much you're interested in seeing an encore performance of the Jo Noah Boogie (as long as Lundquist joins in).
As much as all of that stuff -- location, momentum, dance moves, etc. -- matters, my most basic tenets of bracket-picking involve the laws of efficiency. I did a post at the outset of last year's Tourney Blog titled "Defending Your Bracket," which was reasonably successful in pinpointing the attractive offensive teams that were flawed on D -- and therefore risky bets in the dance. As the chart below shows, in the Modern Era of kenpom.com stats (2004-07), only one team outside the top 75 in adjusted defensive efficiency (sweet-shooting West Virginia, in '05) has reached the Elite Eight, and zero teams outside the top 25 in ADE have reached the Final Four.
Profile Of The Elite Eights
Adjusted Off. Eff. (Nat'l Rk.)
Adjusted Def. Eff. (Nat'l Rk.)
Based on the data above, it behooves you to limit the number of defensively challenged teams you put in your Elite Eight and Final Four. When my SI.com Writer Bracket comes out on Tuesday, it'll only have one school outside the top 50 in defensive efficiency winning more than two games: Texas. And the 'Horns, at No. 59, are barely outside of that range.
It's easy to become infatuated with entertaining offensive teams that don't play D -- Gonzaga's Adam Morrison squads were the best example -- but recent history shows that poor defensive efficiency numbers are a red flag, no matter how well a school scores. Below is a list of the teams (from '05 and '06) that ranked in the top 25 in offensive efficiency but outside the top 75 in D. You'll notice that most of them didn't last too long in the dance:
2005's defensively challenged 1-6 seeds:
Team Off. Eff Def. Eff. Out (Seed) (Nat'l Rk.) (Nat'l Rk.) Rd. Out LSU (6) 112.1 (22) 94.7 (84) 1 Gonzaga (3) 115.5 (10) 97.0 (119) 2 W. Forest (2) 120.8 (2) 94.0 (76) 2
The main attractions here were Brandon Bass, Morrison and Chris Paul -- all of whom could light up a scoreboard. None of them made it past the first weekend.
This club included Morrison (again), Jared Dudley and Craig Smith, Shannon Brown, Chris Lofton and Kevin Pittsnogle. Two suffered first-round exits. Only West Virginia outperformed its seed expectation, reaching the Sweet 16 as a No. 6. None of them won more than twice.
The intriguing thing about the 2007 bracket -- and perhaps this is a result of smarter seeding by the selection committee -- is that only one school seeded 1-6, Vanderbilt, falls into the top-25 offense, below-75 defense category. There isn't a statistically fraudulent No. 1, 2 or 3 seed in the field. There are, however, four teams seeded either No. 7 or 8 that fit our profile, and each one has a talented scoring star:
If you were thinking about going out on a limb and forecasting a Nick Fazekas-led sleeper run into the Elite Eight, I strongly urge you to reconsider. Nevada does seem like an attractive option at first glance; the Wolf Pack dominated the WAC for much of the year, and have three potential NBA players (Fazekas and guards Marcellus Kemp and Ramon Sessions), but they've been keeping a little secret in Reno: their D is suspect. While the teams in this group aren't guaranteed to be doomed -- I think Arizona and Vandy have one win in them apiece -- their potential as giant-killers is limited.
Since we're dealing with such a small sample size (just three seasons) of efficiency data, the conclusions we're making are admittedly unscientific. I wouldn't be surprised if Texas, a young team that got exponentially better in the backstretch of the Big 12, crashes the party in Atlanta with a defense that doesn't exactly fit the Final Four mold. But when it comes to picking a national champion, it's impossible to ignore that the profile of the past three winners includes a top-10 ranking in both offensive and defensive efficiency.
In the grid below, I've broken down the Nos. 1, 2 and 3 seeds from the 2007 bracket into four flights: "A" teams currently have national-champ efficiency resumes; "B" teams are great in one category, and right on the fringe in the other; "C" teams are another step down, and the "D" teams are unlikely to win the title. It's not surprising that three 1-seeds are in Flight A, take a look at Texas A&M: the third-seeded Aggies appear better-suited to cut down the nets in Indy than any of the No. 2s.
Team Off. Eff. Def. Eff. (Seed) (Nat'l Rk.) (Nat'l Rk.)