The best measurement of a quarterback is how they fared against a defense relative to all other quarterbacks that also faced that defense. That removes the element of schedule strength because the best game that the Ravens allowed may only be an average one from a lesser defense.
The Top-8 fantasy performances against each defense were arrayed and each quarterback were recorded for how often they were in the Top-8, the Top-4 and Top-1 versus a defense last season.
Adding up those numbers yields a BTA score since they are better than the average quarterback that faced a defense. It also weighs the performances since a Top-1 also counts as a Top-4 and a Top-8.
Bottom line – this is about how well a player did against a defense relative to all the others in his position did when they faced them.
Josh Allen and Kyler Murray tops the list after great fantasy seasons for young quarterbacks. Aaron Rodgers was an extreme anomaly, turning in an NFL best 15 instances of a Top-8 performance versus their opponents, and even nine of the Top-4 and yet somehow never managed to produce the best game versus any defense that he faced.
Otherwise, not many surprises. Justin Herbert was astounding in his rookie year and already earned a spot among the elite quarterbacks. Lamar Jackson and Dak Prescott topped this listing last year, along with Jameis Winston. Prescott and Winston did not play much in 2020, but Jackson lost the effect from all the touchdown passes in 2019.
This is the list of quarterbacks that posted the best fantasy game allowed by an opposing defense all year for 2020.