The Advanced Stat of the Week this week is Passer Rating Differential.
Passer rating has scores of critics. The most common complaints are that it overvalues completion percentage, it has no opponent adjustment, it has no way of adjusting for game situation, it doesn't value running at all, it doesn't account for sacks or fumbles, it is ridiculously hard to calculate and it was scaled in the 1970s, making it notoriously useless for comparing quarterbacks of different eras.
Other than that, it's great!
Actually, I have always had a soft spot in my heart for passer rating. Aside from the fact that it correlates well with winning, it always seemed like the stat that Joe Montana led the league in, and that has to count for something, right?
I realize that I'm being uncharacteristically kind-hearted to the deeply flawed and possibly useless number, but passer rating is here to stay, and is still infinitely more useful than ranking teams and players by yards. Passer rating is so painfully mainstream that addressing it as an "advanced stat" would make a mockery of the holy name of advanced stats.
So, this week I'm going to tip my hat to our dear, lame old friend and address Passer Rating Differential.
Passer Rating Differential (PRD) essentially compares offensive and defensive passer ratings. One of the reasons I enjoy it so much is that the top eight teams in PRD all made the playoffs in 2011. It covers the gamut of teams from the Packers and Saints (great offensive passer ratings, mediocre defensive ones) to the Ravens and 49ers, who posted outstanding defensive numbers.
PRD shows us that it doesn't matter what combination you use to get the job done, stopping the pass and passing the ball is the key to winning in the NFL.
Today, we look at the Titans, who were middle of the pack both offensively and defensively. The Titans posted a PRD of minus-0.7, good for 15th in the NFL. Tennessee was 14th in offensive passer rating and 18th in defensive passer rating. Subsequently, they finished 9-7 and in the middle of the pack in the NFL, overachieving slightly.
The good news for the Titans is that their defensive passer rating was better than four playoff teams.
Their offensive passer rating was better than three playoff teams.
They don't have to get much better at both sides of the ball, but they do need to get better on either side of the ball. Their PRD of minus-0.7 needs to go up 13 to 15 points total for them to be taken seriously as a legitimate playoff contender.
That difference can come on offense or defense, or merely be an aggregate of modest improvements on both sides. The Titans aren't far off, but they haven't arrived either.