College football rankings: Ohio State hanging onto No. 1 in AP Top 25, but computers disagree

Ohio State is still the No. 1 team in this week's AP Top 25, despite only narrowly beating Indiana on Saturday. That win cost OSU first-place votes in the polls, but the Buckeyes' signs of weakness have the computer ratings, particularly S&P+, unconvinced.

Week 5 brought a bunch of noteworthy, impressive wins for ranked teams. Florida beat up on Ole Miss, in the process picking up an exciting transitive victory over Alabama, which itself put a substantial hurting on Georgia -- in Athens, no less. Roughly 80 miles north of there, Clemson stopped Notre Dame in the nick of time. And farther north still, Michigan whomped Maryland for the Wolverines' second consecutive shutout.

If the week taught us anything, it's that some of the sport's biggest conferences are every bit as wide open as we thought beforehand. Look to the Big Ten, where Northwestern could legitimately play in the conference title game and Ohio State could legitimately not. Look to the Pac-12, where Cal and Utah are playing next week with real league title aspirations on the line. Or look to the SEC, where Alabama somehow smells a lot like a Playoff team yet again.

The rankings we use

The Associated Press Top 25: The longest-running and best-respected human poll. Didn't have any official bearing on the latter years of the BCS, and won't have any official bearing on the Playoff. Expect it to set the course for the committee, however, as most outlets (including SB Nation) will use the AP's rankings as the standard until the committee takes over in November. Usually comes out on Sundays about 2 p.m. ET.

The USA Today Coaches Poll: Formerly part of the BCS, and now just a poll. It tends to be more conservative than the AP's. Though polling athletic departments in order to rank other athletic departments is dubious, we still want multiple human polls in here, and this is the other big one. Releases early Sunday afternoons.

The Massey computer composite: A collection of ... every rating out there, which will be included as soon as it is updated. By including it here, we're giving extra weight to the two human polls, since they're already two of the dozens of ratings included in the Massey. It changes over the course of the week as more rankings arrive.

Bill Connelly's S&P+ ratings: Connelly's efficiency- and explosiveness-based metric parses each team's performance and adjusts it for strength of opposition. These ratings ultimately become part of each FBS team's advanced statistical profile. They're entirely computer-generated and don't signal an agenda against anybody's favorite team.