The Houlgate Perspective Week 15 - Breaking the Ties that Bind
My grandfather, Deke Houlgate I, left behind a very good College Football rating system for his day. Many games resulted in ties and tie games continued until the overtime rules kicked in in 1996. Deke addressed the question of how to score ranking points when teams tied. When a tie occurred, both teams kept their letter grade and each team gained half the number of points allotted for beating a team of that grade. For example, if Stanford, a B team, tied Cal, a C team, Stanford would remain a B team and gain three points, Cal would remain a C team and gain 3.5 points.
The subject of ties brings me to the question of why teams tie in ranking points and can anything be done to resolve them. The prevalence of tied rankings throughout the season is a subject that has concerned me since putting the Houlgate Rankings up on the Internet. In week 14, the de-facto end of the season there were 26 instances in which two or more teams tied for the same ranking. These ties were defined by two or more teams with the same letter grade, scoring the same number of points. Among them were 19 2-way ties, five 3-way ties and two 4-way ties, innvolving 61 teams, slightly more than half of all of the teams in the FBS. This led me to consider ways to break these ties, but without compromising the the legacy ranking system.
I came up with a battery of tie-breaker tests that would ensure the legacy element and distinguish each team in the Houlgate Rankings. To explain these factors, I would like to start with describing the existing ranking conditions and then present the tie breaking factors in sequence.
1. Ranking points: The sum total of a team's ranking points is the supreme measure of the Houlgate Rankings. If your team beats a team with a winning record, you get a handsome return of ranking points. They are the primary measure of your team's success. The team with the most ranking points is No. 1.
2. Letter Grade: The letter grade, derived from your team's number of losses indicates overall success on the field. When two teams score the same number of ranking points, but one team is an A the other a B, the A team has enjoyed more success on the field and deserves to be ranked higher.
3. Strength of Schedule Grade Point Average (SOS_GPA): This is the first of the new tests for breaking ties between two teams with the same number of points and the same letter grade. The rationale here is, if two teams are tied in such a way, the team with the stronger schedule deserves the higher ranking. The SOS_GPA is calculated by taking the grades of all of a team's opponents, assigning a numeric value to them and getting the average. The numbers start with 8 for A and ending with 1 for H. This calculation is done the same way a student's grade point average gets taken, except in the academic field, an A is a 4 and a B is a 3 and so on. The SOS_GPA is rounded out to the one-thousandth of a point. So, when two teams are tied in points, and have the same letter grade, the team with the higher SOS_GPA gets the higher ranking.
4. Who Beat Who (WBW): What happens when the Strength of Schedule GPA is the same? It happens and it happened in Week 14 more often than not. The next question to settle is, if the two teams are tied in points, letter grade and strength of schedule, did these teams play each other? If they did and one instance of this happened in week 14 (Ohio State and Illinois), which team won? The element of who you played and who you beat kicks in, only this time it pertains directly to the two teams in question. In week 14's case, Ohio State won the game, therefore Ohio State got the higher ranking.
5. Field Score Differential (FSD): Many teams still tied on SOS_GPA and most didn't play each other, what then? Since the teams didn't play each other, but fared the same against measurably equal competition, we drill into the game scores. We take the difference between the sum of all points a team played and the sum of all points scored against that team. The resulting number becomes that team's Field Score Differential. This gives us a way to differentiate how two teams performed against the same level of competition, but never played each other. The team with the higher FSD gets the higher ranking.
6. Field Yardage Differential (FYD): Okay, John, by now you shouldn't have any ties, but what happens if two tying teams wind up with the same FSD? You would think that the FSD would conclusively settle the tie and for the most part, you would be right. But after week 14 of the 2011 season, two tied teams ended up with identical FSDs, Iowa and California! To measure who is better, we have to drill down to their field performance. With ranking points, letter grade, strength of schedule and field scores all the same and these two teams never saw each other, we look at what we've determined to be the absolutely last standard of measure, the yards. We take the total yards gained by the team's offense, plus kick returns and subtract from that the total yards given up by the defense, including kicks returned against that team. The difference then is the Field yardage differential. The team with the most wins the tie-breaker. In this case Cal beat Iowa by a more than 800 yards.
Breaking these ties takes a lot of work, especially when there are so many to break. Ranking points and letter grades change fluidly throughout the season, so I decided that it was best to wait until reaching the end of the season to apply all of the tie-breaking rules, at least for this year. It's somewhat futile to apply them in the first half of the season, when there haven't been enough games played for all the Letter grades to appear. The BCS doesn't begin showing its computer rankings until about week 7 or 8, so there really is no rush. However, it may be feasible to bring the SOS_GPA, WBW and FSD into play during the latter half of the season, thus keeping the ties down to a minimum.
In conclusion, the credibility of a college football ranking system should depend on its ability to tell the world, who is the better team, especially when there is no playoff at the end of the season. Leaving ties on the table, means that that question doesn't get answered and therefore we have no answer to challenge.