Apart from everything already mentioned, there is also the fact that some SOS are only team's you have currently played, and some are the strength of all teams on your schedule (preseason before anyone has played a game still have SOS). Any SOS that includes all games for GT will obviously be pretty impacted by the last game on our schedule. ESPN FPI Resume differentiates this. According to them, we've had the 35th hardest schedule so far, and have the 28th hardest going forward. Things like FEI only consider the games that have been played. It is also important that there is more to it than just "how strong on average were the teams I played" (this is further explained in the final link down below). The "expected number of wins" for good/great teams is different from the average strength across all opponents.
This is GT's different SOS ranks:
Expected losses elite team: 0.48 (71)
Expected losses good team: 2.04 (46)
Expected losses average team: 4.45 (38)
So according to this, an elite team would have a pretty easy go with our schedule, but an average team would be performing exactly as we are +/- half a game.
Massey has some interesting comments about SOS on his pages.
This is how he defines a very rudimentary ranking system to work:
To get the feel for how computer ratings work, you may want to try this iterative procedure(
https://masseyratings.com/faq.php):
- set each team's rating to zero
- calculate each team's SOS to be the average rating of their opponents
- calculate each team's rating to be their average net margin of victory plus their SOS
- go back to step 2 and repeat until the ratings converge
More info: