Early Warnings List reveals contenders, pretenders to watch

Efficiency numbers -- how many points a team scores and allows per 100 possessions, according to kenpom.com's database -- are gradually making their way into the college hoops mainstream, and those are the metrics on which the Early Warnings list is based. They tend to be quite telling about a team's NCAA tournament potential: In the six years kenpom.com has tracked tempo-free statistics, no Final Four team has been ranked outside the top 25 in adjusted defensive efficiency (a figure that factors in level of competition). And only two Elite Eight teams in the past six years have ranked outside the top 50 in adjusted defensive efficiency. Having a decent offense matters, too, but the data shows just how unlikely it is for a non-elite defensive team to make a deep tournament run.

Examine the profiles of the past 48 Elite Eight teams below (or just trust me, and scroll past the chart):

• Oklahoma was the worst defensive squad to make 2009's Elite Eight, and the Sooners' D was still ranked a respectable 36th in adjusted efficiency. North Carolina, which blitzed OU in the Elite Eight, was the worst defensive national champ in the tempo-free database, at 0.896 points per possession, but the Tar Heels still ranked 16th nationally in adjusted efficiency. They were an offensive juggernaut with a good enough D in a year when there was no real challenger to UNC's NBA-stocked roster.

Which AP-ranked teams, then, have efficiency profiles that should be red-flagged? These six are 60th or lower in adjusted defensive efficiency:

• In the chart above, Villanova is the headliner -- a top-10 team with just one loss and a national perception as a Final Four contender. But the Wildcats have the 13th-ranked defense in the Big East, which marks a massive drop-off from last season, when they were the league's fourth-best defensive club, and ranked 15th nationally in defensive efficiency. 'Nova had a three-game run this December in which it allowed at least 1.1 points per possession to Maryland, St. Joe's and Temple.

The rest of the Wildcats' season will be a measure of just how much one defender can matter. Senior stopper Reggie Redding returned from a first-semester suspension on Dec. 19, and was a big factor in blowouts of Fordham and Delaware. When I visited Villanova camp in the preseason, coach Jay Wright said he couldn't foresee another glue guy emerging in Redding's absence -- and mentioned that the 6-5 guard had almost singlehandedly turned the scout team into a defensive force. "He's been killing [the starters] in practice," Wright said. The 'Cats are hoping Redding is a cure-all, but keep an eye on their efficiency numbers early in Big East play. Their problems might run deeper.

• Northwestern fans rejoiced on Monday when their Wildcats cracked the AP Top 25 for the first time since 1969, so I hate to dampen their mood ... but NU's efficiency numbers are that of a fringe-bubble team rather than an NCAA tournament lock, despite the fact that the 'Cats are 10-1. They just don't defend well on the interior, ranking 96th in two-point field-goal percentage.

• New Mexico, like Northwestern, has been one of the best early-season success stories, but the numbers (83rd in defensive efficiency) suggest that the Lobos aren't the best team in the Mountain West. That would be BYU, which you'll hear about later.

Only five teams have efficiency profiles that make them look like true Final Four threats:

• Texas has a bigger efficiency margin than the AP's No. 1 team, Kansas, but I don't consider that stat to be significant. Which starting backcourt would you rather have in the NCAA tournament -- Sherron Collins and Tyshawn Taylor, or Dogus Balbay and Avery Bradley? (Balbay and Bradley aren't bad ... but Collins and Taylor are going to be first-round draft picks next June, and Collins has already played in a national title game.)

• The question I'm assuming most of you asked after seeing that chart: Where's Kentucky? The Wildcats have the biggest gap between their national perception (as a team that could go undefeated) and the efficiency numbers (they rank 15th in offense but 49th in defense). UK's problem is that while its defense has been excellent in its biggest games -- on Dec. 5 it held North Carolina to its lowest efficiency rate of the season (0.894 points per possession), and on Dec. 9 it held UConn to its second-lowest rate (0.884) -- but hasn't been consistently stingy. Miami of Ohio, Sam Houston State, Indiana and Austin Peay (all teams outside of kenpom's top 125) scored more than 1.0 points per possession against the Wildcats. Maybe John Calipari's freshmen need another few months to become defensively sound, or maybe they're just bored by non-marquee games ... but either way, they're more upset-prone than the other contenders.

• The other top-five AP team missing from the contenders list is Purdue, which has a top-10 defense but ranks 47th in offensive efficiency. The Boilers' long-range shooters have been frigid -- Robbie Hummel is hitting just 28.6 percent of his threes, and Keaton Grant is making just 20.6 percent -- and they miss injured point guard Lewis Jackson, who was their best backcourt athlete. I wouldn't write Purdue or Kentucky off for a potential trip to Indy, but neither team has been statistically elite thus far.

Last season's prime sleeper pick -- a team outside the AP's top 30 with a solid profile -- was Missouri, which was getting very little national attention at the time, but went on to finish third in the Big 12 and reach the Elite Eight. Not a bad call. Keep an eye on these seven unranked clubs for the rest of the season:

• BYU, which has been kept out of the top 25 by lack of a marquee win or TV exposure, is the team to watch in the above chart. Point guard Jimmer Fredette is a breakout star -- he hung 49 points on Arizona Monday -- and the Cougars' offense has yet to peak, even though it ranks 10th in efficiency: Gunner Jonathan Tavernari has hit only 28.3 percent of his threes thus far, after making 38.1 last season.

• Mississippi State fell off the national radar after it lost to Rider and Richmond in November, and didn't get top recruit Renardo Sidney eligible for the first semester. The Bulldogs' defense is still strong, though -- led by senior Jarvis Varnado, they're ranked first in the country in two-point field-goal percentage allowed, at 36.4.

• Under normal circumstances I'd be hesitant to put USC on the sleeper list. The Trojans' season offensive numbers are atrocious. But they added Charlotte transfer Mike Gerrity on Dec. 19, and have been excellent with him running the point, beating Tennessee, St. Mary's and UNLV. The 1.104 points per possession they scored against Tennessee was the most the Vols have allowed this season. If USC's offense can maintain a decent level of efficiency, Kevin O'Neill's club could have a similar statistical profile to Purdue. That's something that no one expected to say back in November.