I personally believe the Associated Press and USA Today Top 25 polls are worthless. The media and coaches obviously can't possibly follow every game in the country. So does that mean you should lean against ranked clubs against the spread often?
Breaking Down The Polls
Now, let me do say that the new College Football Rankings are valuable because that determines who plays in the national semifinals. That's made up of a very informed group of people whose sole job -- at least in that regard -- to learn everything they can about what's going on in college football all across the country. So exactly like the NCAA Tournament committee. By comparison, the media members in the AP poll often show a bias toward whatever region of the country said media member is located in for obvious reasons. Those are the games they see. SEC beat guys are going to lean toward SEC teams in the polls, etc. Frankly, the coaches voting in the USA Today 25 is a joke because they have much better things to do than follow other clubs and not exactly a ton of free time. Usually they designate someone to vote for them.
That said, the polls often do get it right when starting a season. While the College Football Rankings won't come out until October, the AP and USA Today polls will be released early next month. Last season the Top 3 teams in the preseason AP poll were Florida State, Alabama and Oregon. The Seminoles, Crimson Tide and Ducks were national semifinalists. National champion Ohio State was No. 5 in the poll, behind No. 4 Oklahoma. The USA Today's Top 3 were FSU, Alabama and the Sooners, with Oregon No. 4 and Ohio State No. 6. So those polls turned out pretty accurate except for Oklahoma, which was a massive disappointment at 8-5.
And that's another thing I would take with a grain of salt on the preseason polls: sometimes voters put way too much credit in what a team did in a bowl game the previous season. Oklahoma was rated so high entering 2014 because OU pummeled Alabama in the Sugar Bowl following the 2013 season. What the voters perhaps didn't realize was that the Tide really weren't all that interested in that game after their national title hopes were dashed in the Iron Bowl against Auburn. Two teams that I believe will get too much love from voters this preseason are TCU and Georgia because of dominant bowl wins over Ole Miss and Louisville, respectively.
Don't Fall For Trap
Naturally, college football odds makers play off the public's interest in the polls and generally over-inflate the value of ranked teams (especially if it's Notre Dame). I mean, do you realize that Alabama hasn't been an underdog since the 2009 SEC Championship Game against Florida? That's absurd. Florida State didn't lose a regular-season game last year (or ACC title game) and was favored in all of them. The Seminoles had one of the worst ATS records in the country at 3-10.
But we know rankings are overrated because we often see an unranked team favored over a ranked club. I did find one interesting statistic entering last bowl season. According to Sports Insights, unranked teams were 39-25 vs. the spread against ranked teams over the last 64 bowl games. There were four such games last bowl season under that scenario. Two unranked teams covered.
-Colorado State was unranked and a 2.5-point dog against No. 23 Utah in the Las Vegas Bowl and the Rams were routed 45-10.
-Duke was unranked and a 7.5-point dog against No. 15 Arizona State in the Sun Bowl and the Blue Devils lost 36-31.
-Oklahoma was unranked yet a 6-point favorite against No. 18 Clemson in the Russell Athletic Bowl and the Tigers rolled 40-6 despite missing their injured starting QB.
-Finally, unranked Notre Dame was +8.5 against No. 23 LSU in the Music City Bowl and the Irish beat the Tigers 31-28.
My recommendation is to lean more toward unranked home teams facing teams ranked lower in the polls, at least 15 or worse. From 2007-14, one study indicated that unranked teams had a 430-371 ATS mark against teams ranked from 15-25.
And as noted above, the best time to take advantage of wagering against ranked teams is early in the season when we still aren't clear what clubs are yet. TCU wasn't ranked to start last season but finished No. 3 in both the AP and USA Today final Top 25 polls. The Frogs were also a national-best 11-2 ATS against the spread in 2014.