By Allan Maurer
ATLANTA—The University of North Carolina’s basketball team is most likely to win the Final Four and the other teams most likely to compete in the tournament are Pittsburgh, Memphis, and Louisville, according to a computer system developed by Georgia Institute of Technology engineering professors. The system consistently predicts NCAA basketball rankings more accurately than the AP Poll, the ESPN/USA poll, the Ratings Percentage Index and even the Tournament seeds.
Called the Logistic Regression Markov Chain (LRMC), the college basketball rankings system is designed to use only basic scoreboard data, including which teams played, which team had home court advantage and the margin of victory.
It was originally designed by Joel Sokol and Paul Kvam and has been maintained and improved by Sokol and George Nemhauser, all three optimization and statistics professors in the Stewart School of Industrial and Systems Engineering at Georgia Tech.
Sokol tells TechJournal South that despite the system’s accuracy, “There are always upsets. About half the time the best team does not win.”
The LRMC has ranked North Carolina number one for a month and a half, and ranked Kansas as the best Big 12 team well ahead of other systems.
The system correctly picked all four of last year’s finalists. Counting last year, the LRMC method has identified 30 of the last 36 Final Four participants (83 percent accuracy over the past nine years of NCAA tournaments) as one of the top two teams in their region.
Over the same nine-year stretch, the seedings and polls have correctly identified only 23, and the RPI indentified 21.
Last year, the system correctly chose Kansas as the eventual top team, although UNC, UCLA, and Memphis were the top ranked teams in most other systems.
LRMC seems to have a particular knack for predicting good bubble teams and identifying the top teams. In addition to correctly picking the Final Four, LRMC also correctly identified several over-rated and under-rated teams as potential upsets in 2008.
LRMC differs from other computer rankings systems in two important ways. When determining the value of home court advantage, LRMC considers how much playing at home helps a team win rather than how many points playing on a home court is worth.
Georgia Tech researchers have also been able to show that very close games are often “toss-ups,” meaning the better team barely wins more than half the time.
So, they determined that winning a close game shouldn’t be worth as much as winning easily, and losing a close game shouldn’t hurt a team’s ranking as much as losing badly. LRMC’s ranking methodology takes this into account.
Similar to other rankings systems, LRMC also uses the quality of each team’s results and the strength of each team’s schedule to rank teams.
The system takes the emotion out of rankings, leading to more accurate results.
“As fans, we only get to see most tournament teams two or three times at most during the season, so our gut feelings about a team are really colored by how well or poorly they played the few times we’ve been watching,” said Sokol.
“On the other hand, our system objectively measures each team’s performance in every game it plays, and mathematically balances all of those outcomes to determine an overall ranking.”
For the LRMC rankings see: www.finalfour.gatech.edu
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