Monday, April 11, 2005
Efficiency Margin and Why It Matters
Other Titles Considered
- Do people respect Louisville and Michigan State now ?
- How Iowa got HOSED by the selection committee
- Duke got a seed they didn't deserve? You're kidding.....
Basketball, like most sports, is a simple game. Score more points than your opponent, and you win. If your offense is terrible, you can still scrape by if you allow fewer points than you score. Likewise, a high-octane offense can make up for a porous defense. It's when a team excels at both aspects of the sport that it distinguishes itself from the competition.
This concept is nothing complicated or even recent; Bill James created his formula to compute a baseball team's expected win-loss record based on its runs scored and allowed back in the 1980s. His idea is adaptable to any sport - the more you outscore your opponents by (on average), the more wins you're expected to accumulate over a season. In a single game or series of games between two teams, the team with the greater scoring margin has a greater chance of victory (assuming the previous records were compiled against equal competition).
I spent some time exploring this idea when I looked at Big Ten teams and their expected winning percentage based on the points they scored and allowed. Today I want to expand my view to all major conference teams. I want to see which teams had the best chance of winning come tournament time based on how much they outscored their opponents during the season. My method was as follows:
- I computed offensive efficiency and defensive efficiency (points per possession) for each team from the Big Ten, ACC, Big XII, SEC, Pac-10, C-USA, and Big East.
- Points per possession (instead of points scored/allowed per game) was used in order to eliminate any pace bias.
- Since I wanted each team to have fairly similar schedule strengths, I only looked at conference games. Of course all conferences aren't equal, but there's much less variability in conference schedules than full-season schedules.
- I subtracted defensive efficiency from offensive efficiency to arrive at what I call, for lack of a better term, Efficiency Margin.
For example, Syracuse scored 113 points per 100 possessions during their 16 Big East contests. Their defensive rating during that time was 106, which leaves an Efficiency Margin of 7 (actually 7.8 because of rounding).
The most interesting thing about this list is the top. The four teams who had the biggest spread between offensive and defensive efficiency during their conference seasons were, believe it or not, the same four teams who matched up in the Final Four. Here's a list of the major conference teams with an Efficiency Margin (EM) greater than 10, along with their offensive and defensive efficienies.
My crack about Louisville and Michigan State basically comes down to the seeds they ended up with - a #4 and #5, respectively. Louisville went 14-2 in C-USA, won their conference tournament, and came into Selection Sunday having won 18 of their last 19 games. Considering the stock the committee put into some other conference tournaments, this looked like a solid tournament resume, but Louisville ended up with a seed that placed them as only one of the top 13-16 teams in the country.
Michigan State was constantly trying to erase the "inconsistent underachiever" label it had been saddled with all year, despite their steady and often superb play.
My next beef, of course, comes from Iowa getting paired with Cincinnati in the first round. It seemed like a tough but winnable game at first glance, but in retrospect, Cincinnati looks quite a bit tougher than a 7-seed. They had C-USA's second-best offense and third-best defense, and their second-best Efficiency Margin was double that of third place. Here's the top five EM's from C-USA this season -
Despite some early struggles, Memphis proved to be a decent team by making the Final Four of the NIT. Charlotte was also a 7-seed in the NCAA, and UAB pulled off an "upset" of LSU in the first round. I use quotation marks because UAB had the better EM of the two teams.
The other 7 seeds in the tournament were Southern Illinois, Charlotte, and West Virginia. Yes, I know UWV made the Elite Eight, but they were a cinderella team if there ever was one - their EM was actually -4.1. They lost 5 of their first 6 conference games, including 2 by a combined 58 points, before turning things around for their season-ending run. No disrespect to the other 7 seeds, but I don't think Cincy was quite down to the same level as them. Cincinnati no doubt got burned by the seeding too, as they had to face a 2-seed (Kentucky) by the second round, instead of the easier 2nd round game they would've played had they been seeded properly.
I suppose this was another season of Coach K and Duke getting the benefit of the doubt from the committee based on their tournament history. The Blue Devils beat three average teams in the ACC tournament and suddenly their third place, 5-loss regular season was overlooked. Boooo.
I didn't realize Alabama played so well during their conference season, and I'm surprised they were such a trendy pick to get upset by UW-Milwaukee.
Villanova seems to be the new trendy pick to make a run in next year's tournament. I was a pretty big fan of their program this season (woo, I partied there once when I was an undergrad), and with all the guys they have back next year, I don't think I can stop myself from jumping on the bandwagon. The Big East is going to be crazy - Louisville, Cincy, UConn, 'Nova, Syracuse, West Virginia....
This list of 17 includes 10 Sweet Sixteen teams, six Elite Eight teams, and all four members of the Final Four. Maybe I'll do my wallet a favor next year and let my spreadsheet make my bracket picks.
In retrospect, there were some terrible teams in the C-USA last year, so I probably overstated how good Cincinnati was, which means that Iowa didn't get quite as "hosed" as I thought they did when I wrote this post.Post a Comment