August 25, 2018 - by Tom Federico
Here are the official TeamRankings 2018 college football preseason rankings, including the TR Preseason Top 25.
Our 2018 college football preseason rankings are almost 100% data-driven. We’ve used team data from past seasons to identify descriptive statistics that have correlated strongly with high end-of-season power ratings. We then used those stats to create a model that predicts what a team’s power rating will be at the end of a season.
Some examples of data points used in the model include:
We assign each input factor a weight based on its demonstrated level of predictive power. The output is a projected end-of-season power rating that represents how many points above or below average we think a team will be this coming season, with a 0.0 rating representing a “perfectly average” team.
Once we generate our initial preseason ratings for college football, we eye test them against the both betting markets and the human polls.
If our ranking for a team seems way out of whack with those other sources, we’ll investigate more, checking for some out-of-the-norm factor not taken into account by our model that’s shaping public and/or betting market perception of a team. In some cases, we’ll manually adjust our rating to be a bit closer to the consensus.
However, only rarely will we adjust our numbers all the way to match the market consensus. Predicting how good a team will be before the season starts (especially for a sport like college football with 130 teams to project) is one area where the betting markets and human experts have proven to be good predictors overall — but certainly not gospel.
For example, last year one of our biggest preseason outliers vs. the AP Poll was TCU. Our preseason rankings had TCU at #18; the AP Poll had them at #26. TCU ended up going 11-3, finishing 12th in our predictive rankings, and 9th in the end of season AP Poll. (Ironically, by the end of the season the human voters, after underestimating TCU in the preseason, were even higher on TCU than our system was.)
Since our preseason ratings also drive our college football preseason projections, contrarian opinions of teams can also reveal value betting opportunities. Last season, for example, Vegas bookmaker CG Technology set Nebraska’s preseason win total at 6, with extra juice (-125) to bet the over — implying that over 6 wins was more likely for Nebraska than under 6 wins. Based on our preseason ratings, however, our projections only expected 5.4 Nebraska wins, a strong vote for the under. Nebraska ended up going 4-8 and the unders cashed.
Similar to last year, our preseason ratings have a clear top two, only this year it’s #1 Alabama and, in place of Ohio State last year, #2 Clemson.
Dropping down a bit in team quality, Georgia slots in at #3, with #4 Wisconsin slightly behind. It’s worth noting that our top six teams this year show strong consensus with the preseason AP Poll, with only Washington (#5 TR, #6 AP) and Ohio State (#6 TR, #5 AP) flipped.
After our top four, #5 Washington, #6 Ohio State, #7 Auburn and #8 Oklahoma make up a trailing pack of four teams that we rate very closely; the difference between Washington and #8 Oklahoma is only 0.4 points, so don’t read too much into ranking differences there.
From there the team ratings drop again, with the next-best team, #9 Notre Dame, projected to be almost a touchdown worse on a neutral field than #1 Alabama. Still, out of the top 15 preseason teams this year, Notre Dame and #11 Michigan look like our slightly contrarian picks to be better than the AP voters expect.
As the 2018 season progresses, the impact of these preseason ratings will gradually decay, and actual 2018 game results will play more of a role in determining our team power ratings.
What Does “Better Than The AP Voters Expect” Mean?
Comparing our rankings to the AP preseason rankings is a very imprecise, hand-wavy type of exercise. In the case of Michigan, for example, all we are saying is that our preseason rankings project that Michigan will end up as the 11th strongest team in the nation at the end of the year, vs. the 14th, where they are ranked in the preseason AP Poll. Two takeaways there:
Here are some other TR vs. AP comparisons:
In the TR Top 25 but not the AP’s. Two teams in the TR Preseason Top 25 did not rank in the AP’s version:
TR likes them more than the AP does. Other teams we ranked higher than the AP voters include:
In the AP Top 25 but not TR’s. Two teams in the AP Preseason Top 25 didn’t make the TR Top 25:
The AP likes them more than TR does. Other teams we ranked lower than the AP voters include:
Dear Hardcore Fan Of Team X,
Before you read the preseason rankings below and potentially become enraged because we think your beloved alma mater is going to be much worse this year than you do, please keep two things in mind:
|TR Rank||AP Rank||TR Difference||Team||TR Rating|
|43||San Diego St||5.1|
|119||N Mex State||-17.0|
|122||San Jose St||-19.0|
|130||TX El Paso||-26.2|
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