[terry]

The next step is to think about F+ and what does it really measure versus everything else one could use to measure a defense.

F+ does seem to have some strengths, but there are several things that concern me. One is that while they describe the metric in some depth in words, I don't believe they have published enough detail that one could reproduce their numbers on one's own.

More fundamentally, I am suspicious of two things that are done here: one any statistic that is too complicated to simply understand [inherently what does a defensive F+ of 14.3% mean?]; and I also think that a complex, qualitative question like "how good is a defense" cannot be answered by one number regardless of the algorithm. 

I absolutely agree. I don't like metrics that just don't make any intuitive sense.

And I agree that Steve Durrett's RPRs do make intuitive sense.

[terry]

The next step is to think about F+ and what does it really measure versus everything else one could use to measure a defense.

F+ does seem to have some strengths, but there are several things that concern me. One is that while they describe the metric in some depth in words, I don't believe they have published enough detail that one could reproduce their numbers on one's own.

More fundamentally, I am suspicious of two things that are done here: one any statistic that is too complicated to simply understand [inherently what does a defensive F+ of 14.3% mean?]; and I also think that a complex, qualitative question like "how good is a defense" cannot be answered by one number regardless of the algorithm. 

I absolutely agree. I don't like metrics that just don't make any intuitive sense.

And I agree that Steve Durrett's RPRs do make intuitive sense.