How Deep is Your Conference? (Part 2)
In the comments on my post regarding conference depth earlier this week, some questions were raised about the data set I used. Specifically, how does Notre Dame affect the results?
I decided to run the numbers again for clarification. I also added some additional inforrmation on opponents' winning percentage to give a more complete picture of schedule strength.
As a refresher, the goal of the exercise is to depict conference depth in the last decade by negating the impact of each league's top two teams on the conference's overall performance outside the league. I'm limiting the nonconference games under consideration to games against other BCS teams, and I've done two sets of numbers -- one set that includes Notre Dame and one that excludes the Fightin' Irish.
(Note: The "adjusted" results below remove each conference's top two teams from the data used.)
Let's see how things change.
Results
| Conference | Winning % | Opp. Win % |
| ACC | 48.1 | 57.5 |
| Big East | 43.8 | 56.8 |
| Big Ten | 47.5 | 54.8 |
| Big Twelve | 48.9 | 63.8 |
| Pac-10 | 52.8 | 62.1 |
| SEC | 53.5 | 64.8 |
The SEC appears to be the strongest conference, compiling the best record against the best competition.
| Conference | Winning % | Opp. Win % |
| ACC | 48.0 | 63.7 |
| Big East | 44.3 | 56.4 |
| Big Ten | 47.3 | 58.5 |
| Big Twelve | 48.3 | 63.8 |
| Pac-10 | 55.4 | 63.2 |
| SEC | 53.6 | 64.8 |
Removing games against Notre Dame has the greatest effect on the performance of the Pac-10 and Big Ten. This makes sense, as these two conferences tend to play the most out-of-conference games against the Irish.
| Conference | Winning % | Opp. Win % |
| ACC | 47.5 | 62.4 |
| Big East | 44.8 | 56.7 |
| Big Ten | 42.9 | 55.8 |
| Big Twelve | 44.0 | 62.1 |
| Pac-10 | 42.9 | 60.0 |
| SEC | 50.6 | 62.2 |
As noted in the last post, taking USC out of the mix significantly detracts from the Pac-10's performance in the last decade.
| Conference | Winning % | Opp. Win % |
| ACC | 47.6 | 62.5 |
| Big East | 43.2 | 52.9 |
| Big Ten | 42.1 | 55.5 |
| Big Twelve | 43.1 | 62.9 |
| Pac-10 | 47.2 | 61.1 |
| SEC | 51.0 | 62.8 |
Taking ND out of the equation certainly improves the record of the bottom eight teams in the Pac-10. The effect on the other conferences is less pronounced. Again, this makes sense, as the Irish play Stanford annually and have had home-and-home series with Washington State, Washington (twice) and UCLA this decade to go along with two bowl games against Oregon State. Overall, the Pac-10 is 4-16 in these contests.
Conclusions
Returning to the original objective -- measuring conference depth -- I'd contend that Notre Dame should be included in the analysis.
The point of only including teams from major conferences isn't necessarily to rate one league's performance against all the others. Instead, the goal is to gauge the strength of each league's mid- and lower-tier squads. As such, using non-conference games other BCS leagues helps provide a good universe of data that washes out the impact of teams potentially padding their records against weaker competition.
Notre Dame may not be part of a conference, but it has a standing place in the BCS structure and has qualified for three BCS games in the last decade. Therefore, the Irish are essentially on par with teams from auto-bid leagues.
(You could argue that programs like Utah and Boise State should also merit inclusion, but I'll sacrifice perfect for good here.)
Regarding the Pac-10, it's true that the league has played the Irish more often than other conferences. This does skew the non-conference data somewhat for the Pac-10 relative to the other leagues. However, in evaluating the overall depth of the Pac-10, knowing how teams like Wazzu and Oregon St. did against ND has relevance.