Let’s have some fun with the transitive property.
The South Point Casino in Las Vegas released odds Thursday for more than 50 big college football games in the 2018 season. Those go on top of a lot of Week 1 odds already out.
Still, we don’t have odds for plenty of games. But fret not: There is a quick-and-dirty method to guesstimating what the lines will be when they come out, using Vegas’ own numbers.
It involves the simple use of the transitive property, along with the knowledge that home-field advantage in college football is worth anywhere from 3-4 points on a spread.
Here are some 2018 examples:
An easy example is in Week 6: Notre Dame at Virginia Tech
We know two helpful related data points involving these teams:
- Virginia Tech at Florida State -6 (Florida State is 3 points better on a neutral field.)
- Florida State at Notre Dame -9 (Notre Dame is 6 points better on a neutral field.)
If FSU is 3 points better than Virginia Tech on a neutral field, and Notre Dame is 6 points better than FSU on a neutral field, it implies that Notre Dame would be a 9-point favorite over Virginia Tech at a neutral site. Because the game is in Blacksburg, the Irish will likely be around 6-point favorites, accounting for 3 points of home-field advantage.
We can use the same approach even when it’s not that straightforward.
Week 2: Clemson at Texas A&M
There are no common opponents between Clemson and Texas A&M, but there are common opponents between their opponents. This is transitive property a few times removed.
Based on the released lines, Vegas thinks Clemson is 16 points better than South Carolina on a neutral field. It thinks Georgia is 14 points better than South Carolina on a neutral field. Thus, it thinks Clemson is 2-ish points better than Georgia on a neutral field.
Vegas sees Auburn and Georgia as roughly equals at a neutral site. And it sees Alabama as 3.5-points better than either at a neutral site, or 1 point better than Clemson.
Vegas sees Alabama as a 21-point favorite over A&M in Tuscaloosa, or an 17.5-point favorite on a neutral site. Against A&M, Alabama would be expected to be a 14-point road favorite.
Since Vegas sees Clemson as a point worse than Alabama, a reasonable guess at the line using this transitive logic would be Clemson -13 in College Station.
Week 7: Michigan State at Penn State
This one is relatively easy, because there is a ton of connectivity:
- Ohio State -1.5 at Penn State (Ohio State is about 5 points better than Penn State on a neutral field.)
- Ohio State -6 at Michigan State (Ohio State is 9 points better than MSU on a neutral field.)
- Penn State at Michigan -3.5 (Penn State and Michigan are about even on a neutral field.)
- Michigan at Michigan State -1 (Michigan is 3 points better than MSU on a neutral field.)
Based on common opponent Ohio State, Vegas sees Penn State as about 4 points better than Michigan State on a neutral field. Based on common opponent Michigan, Vegas thinks PSU is 3 points better than MSU.
So let’s call it a 3.5-point difference between Penn State and Michigan State on a neutral field, then add 3.5 points or so for home-field advantage. Penn State should be a favorite of about 7 points, according to Vegas’ logic.
Pac-12 title game? Washington v. USC, hypothetically
Here are our data points:
- USC -2 at Stanford (so at a neutral site, USC would be favored by 1 against Stanford)
- Stanford at Washington -13 (so at a neutral site, UW would be favored by 10 against Stanford).
- USC -6 at UCLA (so at a neutral site, USC would be favored by 9 against UCLA)
- Washington -13 at UCLA (so at a neutral site, Washington would be favored by 16 against UCLA)
Using common opponent Stanford, Washington is seen as about 9 points better than USC. Using common opponent UCLA, UW about 7 points better than Stanford.Averaging the two together, it’s reasonable to expect that Washington would be favored by a touchdown over the Trojans at a neutral site.
That’s an easy way to guesstimate lines on your own.
For a more developed method, you can also check Bill Connelly’s numbers here, which are frequently quite competitive with Vegas’ numbers.