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Unboxing the College Football Polls: 2015 Week Three

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Our mathematical nerditry returns for its second season as Jon sorts through both polls as one.

Our top 18 teams are clearly and indisputably above the rest of the field.
Our top 18 teams are clearly and indisputably above the rest of the field.
Thomas B. Shea-USA TODAY Sports

It's time to really get our hands dirty and figure out just what's going on in the voters' heads -- both the writers and the coaches. To that end, welcome to the first installment of this year's Unboxing the Polls segment.

As a refresher, what we do here is math. (Yes, we know, you were told there would be no blah blah.) Because the polls have different numbers of voters, even if only by a single voter -- and, more importantly, because sometimes a poll is missing a ballot for a given week -- what we do is to take the point totals for each team on each ballot, separately, and divide them by the number of voters in that poll. We then add the points per ballot -- which you will henceforth see referred to as PPB -- for each poll together and divide by two to get an average.

And then we rank everyone by that average, because that's the only sensible thing to do.

The net effect of breaking things down by PPB is that it more clearly allows you to see where the voters have teams close together or bunched together, as well as seeing where the voters are drawing a very clear line between a team or group of teams and the team or group of teams below them.

One thing we decided on-slash-realized while doing this last year was that the margin of error, as you will, is about a half a point per ballot. That is, if two teams are separated by .51-1.49 PPB, we consider that to be effectively the same as being separated by one point. So when we look for gaps, we're looking for gaps over 1.5 PPB. Conversely, if two teams are separated by 0.5 points, they may as well be tied. For clusters, three teams within the span of one PPB is a cluster, four teams within 1.5 points, etc.

One flaw, which doesn't appear to be an issue this season, is when a team is ineligible for the coaches poll. That only applies if a team's on probation or if an FCS team is receiving votes in the AP poll; neither of those are relevant in 2015.

With the explanation out of the way, here's this week's combined rankings. "RK" is our combined ranking.

TEAM AP COACHES RK 1ST PPB LW +/- PPBLW +/-
Ohio State 1 1 1 121 24.975 1 - 24.992 -0.016
Alabama 2 2 2 3 23.346 2 - 23.240 0.105
Texas Christian 3 3 3 22.545 3 - 22.626 -0.080
Michigan State 4 4 4 22.074 5 1 19.600 2.473
Baylor 5 5 5 20.671 4 -1 20.801 -0.129
Southern California 6 7 6 18.250 8 2 16.889 1.361
Georgia 7 8 7 17.244 10 3 16.439 0.805
Florida State 9 6 8 16.856 11 3 16.236 0.619
Notre Dame 8 10 9 15.461 9 - 16.462 -1.000
Clemson 11 9 10 15.113 12 2 13.862 1.251
Cal-Los Angeles 10 12 11 14.352 13 2 13.085 1.266
Oregon 12 13 12 13.550 7 -5 18.852 -5.302
Louisiana State 13 14 13 12.847 14 1 11.086 1.760
Mississippi 15 11 14 12.598 15 1 10.660 1.938
Georgia Tech 14 16 15 11.670 16 1 10.299 1.371
Oklahoma 16 17 16 11.048 18 2 8.070 2.977
Auburn 18 15 17 10.476 6 -11 18.854 -8.377
Texas A&M 17 18 18 10.444 17 -1 8.421 2.023
Arizona 20 19 19 6.160 20 1 4.747 1.412
Missouri 22 20 20 4.703 21 1 4.597 0.106
Utah 21 21 21 4.591 24 3 1.951 2.640
Brigham Young 19 22 22 4.479 29 7 0.786 3.693
Wisconsin 24 23 23 2.898 26 3 1.491 1.406
Northwestern 23 24 24 2.147 28 4 0.863 1.283
Oklahoma State 25 25 25 0.956 30 5 0.652 0.304
West Virginia 27 26 26 0.692 31 5 0.290 0.402
Tennessee 29 27 27 0.587 23 -4 3.041 -2.454
Mississippi State 28 29 28 0.548 25 -3 1.610 -1.062
Kansas State 31 28 29 0.522 32 3 0.237 0.285
Temple 26 31 30 0.501 37 7 0.089 0.412
Arizona State 32 29 31 0.441 27 -4 0.917 -0.475
Toledo 30 40 32 0.285 51 19 - 0.285
Duke 45 30 33 0.262 35 2 0.117 0.144
Boise State 33 33 34 0.242 22 -12 4.450 -4.208
North Carolina State 35 34 35 0.217 40 5 0.064 0.153
Florida 36 36 36 0.161 34 -2 0.120 0.041
Miami (FL) 41 32 37 0.151 36 -1 0.093 0.057
Houston 33 46 38 0.147 51 13 - 0.147
Minnesota 37 36 39 0.137 38 -1 0.080 0.057
Memphis 46 34 40 0.103 50 10 0.007 0.095
California 39 40 41 0.088 44 3 0.024 0.064
Iowa 39 42 42 0.080 51 9 - 0.080
Arkansas 38 44 43 0.072 19 -24 7.801 -7.728
Illinois 46 36 44 0.063 47 3 0.015 0.047
Kentucky 46 36 44 0.063 51 7 - 0.063
Michigan 46 42 46 0.039 51 5 - 0.039
Stanford 41 51 47 0.024 47 - 0.016 0.008
Western Kentucky 43 48 48 0.024 43 -5 0.024 -0.0002
Nebraska 46 44 48 0.023 45 -3 0.023 0.0003
Virginia Tech 43 51 50 0.016 51 1 - 0.016
Pittsburgh 46 46 50 0.015 49 -1 0.015 0.0002
South Carolina 46 48 52 0.007 33 -19 0.171 -0.163
Texas Tech 46 48 52 0.007 51 -1 - 0.007
Louisville 46 51 54 - 38 -16 0.079 -0.079
Cincinnati 46 51 54 - 41 -13 0.057 -0.057
Marshall 46 51 54 - 42 -12 0.046 -0.046
Maryland 46 51 54 - 45 -9 0.023 -0.023
Louisiana Tech 46 51 54 - 51 -3 0.007 -0.007

The top five teams are clearly ahead of the rest of the pack, and Ohio State is clearly number one. TCU and Michigan State are within a half-point of one another, but Baylor -- who was fourth last week -- remains close enough to the Spartans to be within one poll position's worth of ballots. After that, it's a big 2.4 PPB drop to USC.

The Trojans, Georgia, and Florida State fall neatly in line, and Notre Dame is within 1.5 points of Florida State. But Clemson is hot on the heels of the Irish, only about a third of a PPB back, and then the pattern continues in normal fashion on down to LSU. So except for some indecision regarding Clemson and Notre Dame, spots 6-12 aren't really in question.

LSU starts a cluster, though. While Mississippi and Georgia Tech are separated by nearly a full point, Georgia Tech is only 1.2 PPB back of LSU and Oklahoma is within 1.8 PPB of the Tigers. Those four teams are perceived in wildly different fashions by the two polls, and they're also being affected by the gravity well of the next team in our ranking: Auburn.

Auburn, of course, tumbled this week. The AP writers punished the Tigers far more severely than did the coaches, and the result somewhat penalized Georgia Tech and Oklahoma. But overall, Auburn is outside the margin we'd consider as part of the cluster. They're also a mere .032 PPB ahead of Texas A&M, this week's craziest entry. The Aggies gained over 2 PPB from last week as a result of Auburn's fall, and massively distanced themselves from the teams below them. Indeed, the PPB gap between #18 Texas A&M and #19 Arizona is by far the largest in this week's ranking, and one of the largest we have ever seen between two adjacent teams: over 4.3 PPB. The problem? Despite gaining so many points, A&M dropped a spot in our rankings, because Oklahoma jumped over the Aggies while Auburn failed to fall past them. A&M is in 17th place despite having earned enough points to be 15th or 16th, all things being equal.

After a long trek through the desert, we come to... the desert, with Arizona. Like A&M, only in reverse, Arizona is offset one place from where their point totals would suggest. But they're still alone on an island, being nearly a point and a half ahead of Missouri. Mizzou, however, start a tight cluster with the two Utah schools; 22nd-ranked BYU is only a quarter of a PPB behind the 20th-placed Tigers. There's another decent gap between BYU and Wisconsin, and then we proceed on out of the top 25 in an orderly fashion after that.

Another reminder necessary from last year: once you start getting into the teams which didn't get ranked in the top 25 by either poll, the gaps disappear in any real sense because you're dealing with teams that got less than a point per ballot in the first place. So our analysis of the un-ranked changes a little. In this case, Oklahoma State is the first team that didn't receive a full PPB, but only barely, and they end up 25th, as they did in both polls. It's a long drop, relatively speaking to West Virginia, and then there's a large cluster stretching all the way down to Arizona State, who has a decent gap on Toledo (which suffered from the coaches not giving them credit for beating Arkansas, who they simply ejected from their ballots altogether).

The big gainer on the week in terms of raw PPB was BYU, earning an average boost of nearly four spots across all ballots. Oklahoma, Utah, Michigan State, and Texas A&M also received notable boosts. Auburn, of course, was the big loser, followed by Arkansas, Oregon, and Boise State. As for changes in the rankings themselves, Arkansas led the way, falling 24 spots. South Carolina, Louisville, Cincinnati, and Marshall all also topped Auburn's 11-point fall. Toledo, to nobody's surprise, earns the award for biggest jump of the week, leaping into the rankings at #32 after receiving no votes in either poll a week ago. Houston, surprisingly, was second; the Cougars vaulted into 38th place from non-existent last week. The largest jump for a team which actually did receive votes last week belongs to Memphis, up 10 spots.

New this week: Toledo, Houston, Iowa, Kentucky, Michigan, Virginia Tech, and Texas Tech. We say goodbye to Louisville, Cincinnati, Marshall, Maryland, and K-State's Saturday opponent, Louisiana Tech.