Thursday, May 9, 2013
Video: QBR and wins above average
By Kevin Seifert
I participated in this Blogger Blitz video with NFC West blogger Mike Sando, mostly because I was the only ESPN.com NFL blogger willing to discuss expected wins above average metrics as it relates to quarterbacks on a 65-degree spring day. (Mike has this post and this post on the topic.)
It's actually simpler than it sounds. You remember Total Quarterback Rating, right? QBR? Well, it can be used to estimate how a quarterback impacts his team's won-loss record.
An average quarterback has a 50 QBR on a scale of 0-100. So if you take the difference between a quarterback's QBR and 50, and then spread that percentage over 16 games, you can calculate how many extra wins (or losses) the quarterback contributed to a season that team would have had with an average quarterback.
The video provides more context and the chart provides the raw data on NFC North quarterbacks. "WAA" refers to the number of wins above average each quarterback has produced per season in their careers, according to QBR analysis. (Jay Cutler's figures exclude his time with the Denver Broncos.)
Three of our four quarterbacks have played above the NFL average since the start of the 2008 season, with the Green Bay Packers' Aaron Rodgers doing the most to elevate his team's win total. Quarterback Christian Ponder's negative WAA means his play has brought down the Vikings' win total by 0.7 games per season.
Many of you will look at this analysis and suggest that Rodgers, Cutler and the Detroit Lions' Matthew Stafford have meant more to their teams than their WAA indicates. The best way to explain that objection is that WAA isn't indicating that. It is a comparative statistic based on the average quarterback's performance, not the sum total of each quarterback's contribution. The goal is to find out how much more the quarterback is adding, or not, to his team's fortunes.