Passer Rating vs QBR, Week 1

I’ve been looking at the NFL age-old Passer Rating stat and ESPN’s quarterbacking stat called QBR, which was instituted a decade ago to address alleged shortcomings in the Passer Rating.

I can sympathize with the desire for something like QBR. Passer rating can shortchange some quarterbacks. For instance, in the 1990s Brett Favre was throwing one-yard touchdown passes while Troy Aikman was handing off to Emmett Smith for one-yard touchdown runs. Favre’s TD% may have been inflated, while Aikman may have thrown for more TDs if his team’s running game hadn’t been so strong. QBR, which evaluates quarterbacks play by play, wouldn’t punish Aikman for handing off.

On the other hand, leaders in Passer Rating not only tend to be the winningest quarterbacks, but also the ones we can tell are the best with our own eyes. Some Hall of Famers like Aikman, Joe Namath, Terry Bradshaw, and John Elway may have had average (for their eras) career passer ratings, but their best seasons in passer ratings were also their most successful in terms of winning games and championships.

The correlation of passer rating differential to winning goes back to the early years of the NFL. As Kerry Byrne wrote in 2011,

67 of 69 champions (97 percent) since 1940 finished the year ranked in the top 10 in Passer Rating Differential. For a little perspective, consider that 68 of 69 champions finished in the top 10 in scoring differential. That’s right. Passer rating is nearly as effective at identifying winners as points.