Though there are many similarities between the AP Top 25 and the rankings that result from Ken Pomeroy's (subscription required) pythagorean expected winning percentage, it's the differences that are far more intriguing.
Differences are certainly to be expected, as the AP rankings are based on what has happened while KenPom's rankings are based on what is expected to happen. However, some teams are ranked very differently in the two polls.
Pittsburgh received a grand total of six votes in the latest AP poll, but KenPom has the Panthers rated as the ninth-best team in the country. Conversely, Baylor is No. 11 in the AP poll and 36th in KenPom's index.
Perhaps most interesting of all, Louisville is ranked No. 6 in the AP poll, but the Cardinals are No. 1 according to KenPom—and by no small margin, either.
But who is "right" in each of these situations?
Let's take a look at the 12 biggest differences between the two ranking systems—six teams that the AP ranks considerably higher than KenPom, and six vice versa—stating each side's case and deciding which is a more accurate representation of that team's spot in the national totem pole.
AP rankings listed on the following slides were posted on December 23. KenPom rankings listed on the following slides are current through December 24.