Sunday Nov 30, 2008
Sunday Nov 30, 2008
I thought it would be interesting to take a summary look at the BCS, polls, and some computer ratings to see how they compare. Below, is such a table with the first number in each cell the current ranking and the second number from 4 weeks ago to see how things have changed.
| Team | BCS | Coaches | Harris | AP | BCS Computers | Schmidt Computer |
|---|---|---|---|---|---|---|
| Alabama | 1/1 | 1/1 | 1/1 | 1/1 | 3/T1 | 7/8 |
| Oklahoma | 2/6 | 2/4 | 4/5 | 4/6 | 1/9 | 1/3 |
| Texas | 3/4 | 3/7 | 3/6 | 3/5 | 2/3 | 2/1 |
| Florida | 4/8 | 4/5 | 2/4 | 2/4 | 6/5 | 3/2 |
| USC | 5/7 | 5/6 | 5/7 | 5/7 | 8/10 | 4/7 |
| Utah | 6/8 | 7/9 | 7/9 | 7/10 | 5/7 | 13/18 |
| Texas Tech | 7/2 | 8/3 | 8/3 | 8/2 | 4/T1 | 5/4 |
| Penn State | 8/3 | 6/2 | 6/2 | 6/3 | 9/4 | 6/5 |
| Boise State | 9/10 | 9/10 | 9/10 | 9/9 | 7/8 | 9/10 |
| Ohio State | 10/11 | 10/12 | 10/11 | 10/12 | 11/12 | 11/11 |
The first observation is that the three polls, while independent and made up of different voters, end up with near identical rankings. This either means that they must be right because they agree, or they agree because they influence each other and the voters use others as input when submitting their votes and they aren't necessarily correct and aren't independent. I suspect it is more of the latter. If I'm right, then you have ask if using two polls it the right way to determine 2/3 of the BCS? If they just follow each other what is the point?
The second observation is that the polls and BCS computers vary quite a bit from week 10 to week 14 (and thus the BCS varies too since it is computed from these). You would think that a ranking system should do a pretty good job of ranking teams where they should be and by week 10 should be pretty accurate and thus a team shouldn't change a bunch by week 14 if the ranking system had things relatively correct in week 10. But looking at the RMS deviation for these you see a range of 2.55 (Harris) to 3.38 (BCS Computers). However, if you take a look at my computers rankings, the RMS deviation is only 2.1. Now if a ranking is just stubborn and doesn't move teams appropriately it could have a small RMS deviation but not be accurate. This leads to the third observation.
The third observation is that the computers, and particularly my computer don't agree that Alabama is the best team in the country like the polls do. So are they correct in doing so? At least my computer has done very well in predicting Alabama games going 8-2 predicting their games against the spread so that would seem to support the ranking. Of course, we have another chance to test this theory with Alabama playing Florida this weekend where my computer has Florida as a nearly 6 point favorite. And my computer is being conservative as Vegas has Florida a 10 point favorite!
So, from the first observation we see the polls aren't very independent and perhaps not objective and that there is little point in using multiple. From the second observation we see that the polls don't tend to have things right and either have to adjust to get them right, or overreact and thus shouldn't be trusted. From the third observation we see that the computers, particularly mine address the first two issues, so perhaps we should throw out the polls and use computer rankings alone!
Not that one week should be the deciding factor (and clearly my computer has picked Alabama games well this year over many weeks), but here are my computers picks for the big games this weekend:
It should be fun to watch!