You don’t have to be a college football expert to know that rankings aren’t an exact science. That became apparent again this week when looking at the difference between the polls put out by the AP top 25 voters and the College Football Playoff committee.

And with the latter being the method that assigns national seeds to teams, determined road and home teams, and who gets a bye, that makes what the selectors think a little more consequential come postseason time.

What were some of the key differences between the AP poll and the playoff rankings?

Selectors love Alabama more than AP voters

Alabama’s AP ranking: No. 7
Alabama’s CFP ranking: No. 3

The selection committee made no secret that they were big fans of what the Crimson Tide did this season. That was despite losing to Georgia and Tennessee, but they papered over those results by judging Bama’s overall strength of record.

AP voters were more critical of what Alabama put on the field in recent weeks, but still took the close game to Georgia into consideration, a commanding win over Kentucky that looked better over time, and a dominant showing at LSU last time out.

AP likes Irish beating Miami more

Notre Dame’s AP ranking: No. 3
Notre Dame’s CFP ranking: No. 5

Notre Dame was the No. 4 team in the AP rankings going into last Saturday, only dropping two places after a four-point loss at BYU before that.

But the selection committee was far more unforgiving of the Fighting Irish quality of schedule, which included no wins against ranked opponents, putting them at No. 11.

Beating No. 1 Miami last week forced a massive overcorrection in the committee room, who propelled Notre Dame up 7 spots to compensate for the dramatic improvement in strength of record after taking out the both AP and CFP top-ranked team.

Playoff punished Hurricanes more for loss

Miami’s AP ranking: No. 5
Miami’s CFP ranking: No. 7

The injury to star wide receiver Malachi Toney combined with the loss at Notre Dame was going to result in a drop for the Hurricanes, but two very different drops.

The one by the committee had to account for two dynamics they set out in the first poll: that they had to give Notre Dame a considerable bump after its win, but also had to find a way to slot Miami behind the Irish.

AP voters didn’t have to account for such a marked increase in Notre Dame’s position, since they kept them a top-five team going in. That allowed for a less dramatic fall for the Hurricanes, which stayed in the top-five on their ballots.

Committee doesn’t like Indiana’s schedule

Indiana’s AP ranking: No. 6
Indiana’s CFP ranking: No. 9

A week ago, the Hoosiers were the No. 4 team in America, according to the committee. A week later, they were No. 9. What happened? Nothing, given they didn’t even play.

But other poll movements by winners and losers concentrated around the CFP top-ten, combined with a new argument from the room that Indiana’s strength of schedule has taken a hit compared with their peers on the right side of the bracket.

Indiana can change that narrative, for better or worse, against USC this Saturday.

Transfer of power in Big 12 standings

BYU’s AP ranking: No. 12
BYU’s CFP ranking: No. 10

Two losses for the Cougars, first at unranked UCF and then at undefeated and highly-ranked Utah, created a dilemma for voters, who responded in different ways.

For the committee, that meant keeping BYU in the top-ten, above reigning Big 12 champion Texas Tech, which sits No. 12 in their ranking, and outside the bubble.

For the AP pollsters, it meant dropping BYU below the Red Raiders, who occupy the Cougars’ No. 10 CFP position in this ballot.

Win out, and the Red Raiders should force the selectors to rethink that order.