ADVERTISEMENT

Chase and the F+

The most concise explanation of F+ is that its a ranking system that measures a team's luck and opponent adjusted performance in relation to all other teams: The system is rating the performance of 130+ teams as if they were all playing vs the same quality of competition and on the receiving end of the same amount of luck over the course of their respective seasons.
 
Last edited:
You're going to give us your professional opinion on whether this algorithm is up to snuff?


That’s impossible unless I can see specific “factors”, coefficients, and weights. Ideally the algorithms. Like an auto-regression?

Most importantly, I think based on what people posted, I get the gist of how F+ calculates power rating. I’ve skimmed and not yet deep dived…but would also like to view its predictive power, if any.

FIFA openly publishes its ELO system. Obviously it’s easier to assess. But it is sometimes really off in using it to predict wins.

My gut is F+ could be useful as a power rating. I’m not sure however on the part the measures offensive efficiency. How well does an offense move vs a defense. Somebody noted a long drive with a fumble loss at the 1 yard line is inefficient?

That is debatable. Sounds like a pretty sophisticated model overall. But I’ve seen extremely complicated models do no better than simpler ones. Reducing factors is actually called Principal Component Analysis (PCA).

For example, you have an age, weight, height, favorite color, NCAA football team, etc. Let’s predict your earnings for the next year. PCA reduces factors like favorite color that the data will show to not affect earnings like your education can.

Same in football. Is a made up factor like drive efficiency meaningful? Even if so, how heavily should it be weighed vs other principal factors. All this by the way is for the most part computed by drawing a line that best fits predicting a dependent variable, like a game result, based on many independent variables…all plotted on a graph.

Even neural networks use weights at nodes. Indicating which path to take. It’s all based obviously on statistical scoring. Again I ultimately need a deeper look.

Like I said I’m skeptical of many of these models to be highly predictive when the phenomena is too complicated…and when it’s a tight prediction, like ND vs Army as opposed to ND vs Penn State. Kinda common sense. Just computes odds, as we all know.
 
Yes "adjusts" or "neutralizes" for luck

Basically these systems separate 'skill' from 'luck' in the performance by ranking teams as if they were all on the receiving end of the same amount of good or bad luck (which means eliminating the impact luck has on the performance of the team) so that they can better understand what teams are good at football and not just good at being benefactors of a bunch of lucky events that happened to go their way.

As an example lets take two separate teams playing in two separate games:

Team 1 had 70 above average plays, and 6 above average drives, but had 3 unforced turnovers, -30 yards in unforced penalties (roughing the passer, a late hit, etc.), and lost the game

Team 2 had 55 above average plays, and 4 above average drives, but had no turnovers, had a pick 6 on a deflected pass, and was the benefactor of a shanked punt and 2 easy missed field goals and won the game

Team 1s opponent was Alabama
Team 2s opponent was Wisconsin

Team 1 obviously outperformed team 2, but team 2 was just far more lucky so despite Team 1 losing, they might have even increased their F+ rating for the week more than Team 2 did.

This is an oversimplified example, and not all special teams gaffes and turnovers are excused away as bad luck in the formula but i hope you get the point im making regardless
lol it’s BE

“Luck” is qualitative at the very least, based on no fact….judgment !
 
lol it’s BE

“Luck” is qualitative at the very least, based on no fact….judgment !
No. "Luck" are stats with really low levels of correlation/low levels of predictability from game to game. "Skill" are stats that are very predictive and have high levels of correlation from game to game.

The system deemphasize luck (high variance events) and puts a lot of weight on data that is predictive. Why? Because predictive data/high correlative data means the data is a reflection of skill.

What data is predictive? How a team performs on offense or on defense from play to play. Or how efficiently teams move the ball and finish their drives and how well they prevent the other team from doing those same things.

What data is not predictive? Unforced turnovers. Unforced penalties. Special Teams turnovers & scores (among others). Despite these high variable events having MAJOR IMPACT on the final score of the game, they are very unpredictable/have very low levels of correlation.

The F+ system is weeding all this noise out of the data (low predictability events) and HONING IN on the signal (the best predictive stats in the sport) and ranking teams based on their ability to achieve these stats

The teams that are ranked really high in F+ are the teams that are really good at producing positive high correlative stats.
 
Games like Saturday are why i say efficiency is a completely backwards looking stat. SC drove the ball down the field twice and then threw two 99 yard pick-sixes. That is the most inefficient thing you can do and it does not make a dime of difference to SC's future point spread.

Also, this is from last week when we are behind Ole Miss. #1 in defensive efficiency but 16th in offense.

 
ADVERTISEMENT
ADVERTISEMENT