Saturday, June 17, 2006

Who Wins Close Games?

Previously on this blog, I've debunked the fallacy that teams have an 'ability' to win close games. Now I want to take another look. Two writers for baseball prospectus, Rany Jazayerli and Keith Woolner, discovered that bullpen strength influences which teams win close games in Major League Baseball. Does team defensive strength have a similar effect in college football? To answer this question I selected the top 5 defensive teams in terms of scoring defense for each of the past six seasons (2000-2005), a sample of 30 teams. Then I selected the top 5 offensive teams in terms of scoring defense for the past six seasons, another sample of 30 teams. Then I determined each team's record in close games (games decided by 1 score = 8 points or less). Here is the year by year examination of the top 5 scoring offense and top 5 scoring defenses in terms of their record in close games.


Defensive Teams Offensive Teams
Texas Christian 0-2 Boise State 1-2
Florida State 1-1 Miami (Fla) 1-1
Toledo 1-1 Florida State 1-1
Western Michigan 2-2 Nebraska 2-1
Miami (Fla) 1-1 Virginia Tech 2-0

Total: 5-7 .417 Total: 7-5 .583


Defensive Teams Offensive Teams
Miami (Fla) 1-0 BYU 5-0
Virginia Tech 0-2 Florida 0-2
Texas 1-1 Miami (Fla) 1-0
Oklahoma 2-1 Fresno State 2-2
Florida 0-2 Hawaii 3-3

Total: 4-6 .400 Total: 11-7 .611


Defensive Teams Offensive Teams
Kansas State 2-2 Boise State 0-0
Ohio State 7-0 Kansas State 2-2
North Texas 2-3 Miami (Fla) 2-1
Georgia 5-1 Bowling Green 1-0
Alabama 2-1 Oklahoma 1-1

Total: 18-7 .720 Total: 6-4 .600


Defensive Teams Offensive Teams
LSU 3-0 Boise State 3-1
Nebraska 1-0 Miami (Ohio) 2-0
Georgia 2-2 Oklahoma 1-1
Miami (Fla) 5-1 Texas Tech 2-2
Oklahoma 1-1 Southern Cal 0-1

Total: 12-4 .750 Total: 8-5 .615


Defensive Teams Offensive Teams
Auburn 3-0 Louisville 2-1
Virginia Tech 4-2 Boise State 3-1
Southern Cal 4-0 Utah 0-0
Florida State 3-3 Bowling Green 0-1
Penn State 1-3 Fresno State 1-2

Total: 15-8 .652 Total: 6-5 .545


Defensive Teams Offensive Teams
Alabama 3-1 Texas 2-0
Miami (Fla) 2-2 Southern Cal 2-1
Virginia Tech 1-1 Louisville 1-1
Georgia 3-3 Texas Tech 2-2
Texas 2-0 Fresno State 0-4

Total: 11-7 .611 Total: 7-8 .467

The 30 strong defensive teams posted a combined record of 65-39 in close games (.625). The 30 strong offensive teams posted a combined record of 45-34 in close games (.570). So it appears strong defensive teams do win more than their fair share of close games. Furthermore, 13 of the 30 strong defensive teams posted winning records in close games, 12 posted .500 records, and only 5 posted losing records. 12 of the strong offensive teams posted winning records in close games, 10 posted .500 records, 6 posted losing records, and 2 had no record.

No statistical study is complete without a control group. To find a control group, I randomly selected 5 teams for each season (numbering each team alpahebtically and using a random number generator) to be the basis for comparison. These team ranged from great (Penn State 2005 and LSU 2003) to medicore (South Carolina 2004) to awful (Duke 2000). Here are those teams and their respective records in close games.


Minnesota 1-4
Duke 0-2
Kansas State 3-1
Southern Miss 3-3
Nevada 2-0

Total: 9-10 .474


Miami (Ohio) 4-3
Mississippi State 2-5
Clemson 4-2
Oklahoma 2-1
Rice 5-1

Total: 17-12 .586


Eastern Michigan 3-1
Louisiana Tech 2-1
Miami (Ohio) 3-3
Virginia 4-2
Colorado 2-2

Total: 14-9 .609


Vanderbilt 0-2
Minnesota 3-2
UTEP 1-2
LSU 3-0
Memphis 1-2

Total: 8-8 .500


Florida State 3-3
South Carolina 2-2
East Carolina 1-2
Hawaii 2-1
San Jose State 1-1

Total: 9-9 .500


Kansas 1-0
Toledo 1-1
Mississippi 2-2
Penn State 3-1
Connecticut 1-1

Total: 8-5 .615

The 30 random teams had a cummulative winning percentage in close games of .551 (65-53). If your memory is short, that is less than the winning percentage of the strong defensive (.625) and offensive (.570) teams. Of those 30 random teams, 14 posted winning records, 9 posted .500 records, and 7 posted losing records. That's actually more teams with winning records, but also more with losing records for the control group.

Judging from this data, strong defensive teams do appear to win more than their fair share of close games. However, there are several important issues to discuss. Foremost, points allowed may not be the best method to rate defenses. Many factors account for scoring points. A team with the best defense may not finish as the top ranked scoring defense if their offense has many turnovers that put them in bad spots or if their special teams do likewise. Perhaps yardage or even yards per play is a better indicator of a defense's true strength. A second problem is schedule strength. The teams in BCS conferences are usually the best defensive teams thanks to the talent they are able to recruit. However, their schedules are also more difficult because they play other BCS schools who are also able to recruit the best talent. For this reason, their points allowed may be higher than small-conference schools that enjoy easier schedules. For example, in 2002 North Texas had the 3rd ranked scoring defense. They shut out 3 teams that season. One of those teams was non-Division IA Nicholls State and the other two were Louisiana Lafayette (averaged 16.92 points per game) and Idaho (averaged 23.75 points per game). The Mean Green did have a stout defense in 2002 (they held Texas, TCU, and Arizona below their seasonal averages), but they were definitely not the third best in the nation. Even though this study is not perfect, something can still be gleaned. Winning close games, while still heavily determined by luck and pure randomness, seem to be a skill that strong defensive teams somewhat possess.

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