Blogging The Boys
We’re going to look at an EPA-based metric to see how today’s NFL QBs hold up under an advanced stats microscope, and to do that, we turn to ESPN’s Total QBR.
Why not simply use the better-known passer rating? Because the trusty NFL passer rating was designed to evaluate the passing game only. It does not account for a quarterback’s running game, his ability to generate first downs, the amount of sacks he takes, penalties, success rate, and many other things.
ESPN’s QBR is an attempt to fix some of the weaknesses of the traditional passer rating. ESPN’s Sharon Katz and Brian Burke explain the concept:
Traditional box score stats distort the performances […] because they (1) fail to account for all of the ways a quarterback can affect a game, (2) don’t put plays into the proper context (a 5-yard gain on second-and-5 is very different from a 5-yard gain on third-and-10), and 3) don’t acknowledge that a quarterback has teammates who affect each play and should also get credit for everything that happens on the field.
Total QBR, much like the Expected Points concept, looks at every single play, adds context (e.g. down-and-distance, score differential, win probability etc.) and then allocates credit to the quarterback and his teammates to produce a clearer measure of quarterback efficiency. Uniquely to ESPN’s Total QBR, the resulting metric is expressed as a number on a 0-to-100 scale to produce a player’s Total QBR.
An average quarterback will have a QBR around 50, and a Pro Bowl-level player will have a QBR around 75 for the season. On a game level, however, a QBR of 75 means that holding all other factors constant (defense, offensive teammates, etc.), a quarterback’s team would be expected to win about 75 percent of time, given that level of QB play.
In the tables further down this post is a look at 45 active NFL quarterbacks (plus Tom Brady, Drew Brees, and Eli Manning, for reasons that will become clear later) and the games they started between 2015 and 2025. In games in which those 45 QBs started, had at least 10 pass attempts, and posted a QBR of 75 or higher, they are a combined 717-164-2 for a win percentage of .812, which is not far from the 75 percent ESPN talks about above.
If we accept that a Total QBR of 75 or more denotes a good game by the QB, it follows that a QB with a lot of 75+ QBR games is a good quarterback.
But instead of simply summing up the number of good games for each quarterback, we’ll use “Good game percentage” (games with a Total QBR above 75 as a percentage of total games started) as our metric of choice. This accounts for the fact that the quarterbacks in this analysis have played a different number of games over the last 11 seasons. Matthew Stafford for example has played 161 games over that span, while Brock Purdy has only...
