Using Betting Markets To Learn About 2023 CFB Teams
How betting markets can be used for info (Even if you don't bet!)
The meteoric growth of sports betting in the US has led to a wealth of easily accessible information. Even if you don’t bet often or have an account with a sportsbook, you can still use the information given to us to see how Vegas views each team in the 2023 season.
With the 2023 season starting in about a week, we can use preseason win totals to rig together a set of power rankings. We will be attempting to adapt the work done in the NFL ranks by Timo Riske at PFF (Link here) and Robby Greer on his NFL ELO Site (Link Here).
2023 Preseason Win Totals
Let’s start with the win totals you can find on this Draftkings sportsbook page (these are always subject to change so the numbers you see may change in a week). For those that do not bet, books will set these numbers and you can bet whether you think a team will go over or under there win total in the regular season. Now here lies our first issue: books will have different odds set for every team. The best way to explain this is by plotting a teams win total vs. the implied odds that they will go over this total.
Note: “Vig” or “juice” is what the sportsbook charges for taking a certain bet. We remove that to the true implied odds.
As you can see, teams like USC/Clemson have higher implied odds to go over their preseason win total of 10 vs. FSU. Seeing as teams are all over the place on this graph, we need to do a little adjustment to the win total based on their implied odds. To spare the mathematical details, the adjustments will move teams with a greater than 50% implied odds to go over higher than their win total, and teams less than 50% lower. This is the final product:
Adjusted Win Totals
Now we have totals that have been adjusted and they are looking pretty good. Compared to the NFL there is a little more movement up and down, but for the most part we don’t see too many seismic shifts. If you’re trying to kill some time, you can actually take these adjusted win totals and divide by 12 (for the amount of regular season games) and you get a teams probability of winning every game. For example, Georgia’s 11.22 adjusted win total means they have a probability of winning every game at 93.5%.
Once you have that percentage, you can apply that to each game of your favorite teams schedule and see what makes sense vs. what might need some adjusting. If you do end up doing some adjusting, sum up those adjusted percentages and bam! You have your very own win total projection, with addition being the only tool required.
This uncovers another issue. Teams can have the same adjusted win total (USC and Alabama) but they can’t be considered equal because they play entirely different schedules. Out of conference matchups can range from powerhouse matchups all the way down to FCS teams. With that in mind, its time to do some adjusting based off of strength of schedule.
Team Strengths
To accomplish this, we have to transform our adjusted win totals into a point spread rating that tells us how many points above or below the team would be vs. an average team on a neutral field. Again, that involves some math computations so we shall skip that part. Once we have our point ratings, we will replicate a simple rating system, which takes into account strength of schedule. We don’t have win totals for FCS teams, so they games will unfortunately not be included. The end result will be a team strength rating that is adjusted for their FBS strength of schedule.
Here is the end result. It should be noted that home field advantage was not included in these calculations (note to self: team specific home field advantage would be a fun idea to try!), so these numbers represent how better/worse a team is vs. an average team on a neutral field. No real surprise at the top as Georgia looks to win their third straight national championship. This also shows us once again that Dequan Finn and Toledo football are must watch TV this season.
We can look at a teams adjusted team strength vs. their FBS SOS to see which teams could be in for a big season in 2023. The further up you go on this graph, the harder their FBS SOS is on average. The further right you go, the stronger your team is. This means that teams in the bottom right quadrant are expected to be strong teams and face softer schedules. This includes teams like Liberty, Toledo etc. for the Group of 5 teams, and teams like Georgia, Iowa etc. for the Power 5. Meanwhile, teams like Michigan State, Indiana and Florida are not expected to be that strong and face a pretty tough schedule.
In terms of conference strength the SEC remains at the top of the list. The SEC and B1G being at the top of the list followed by a gap with the rest of the power 5 conferences feels very…. fitting given everything that is happening off the field. Over in the world of the group of 5, the AAC continues to lead despite some team departures. Following the AAC is the #FunBelt, which is the conference for you if you still believe in regional rivalries in conferences.
Week 0 Implied Points
One last thing we can get from betting markets is a teams implied points in a given matchup. This requires the spread and over/under point total for a matchup. If you divide the over/under point total by 2, you get a base point total for each team. After that, simply divide the spread by 2 and then add that to the base total if they’re the favorite, and subtract it if they’re the under dog. This is what it looks like for the Week 0 matchups next week:
Heisman trophy winner Caleb Williams opens his 2023 campaign against San José State, Notre Dame and Navy kick off the year with a classic rivalry, and we get a sneaky good matchup in San Diego State vs. Ohio. We have made ladies and gentlemen, COLLEGE FOOTBALL IS BACK!!!
Buy Me A Coffee!
https://www.buymeacoffee.com/CFBNumbers
As long as I do this newsletter I will keep it free so that as many people as possible can enjoy and join us on our CFB data adventure. However, if you did want to show additional support the newsletter (which you 100% do not have to!) you can always buy me a coffee here!
If you want to dive in to the data like I do, check out @CFB_Data and @cfbfastR on Twitter, where you can learn how to get started in the world of College Football data analysis!
If you want to see more charts and one off analysis, follow my twitter page, @CFBNumbers