Tennessee Titans Advanced Stat of the Week: No Defense for the Bad PRD

Nate DunlevyGuest ColumnistFebruary 12, 2013

The Tennessee passing game went backwards in 2012.
The Tennessee passing game went backwards in 2012.Phil Sears-USA TODAY Sports

Coming into 2012, the Titans needed only slight improvement on either side of the ball to take a step forward into the playoffs. Instead, they went backwards in a big way.

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 kindhearted 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.

The 2011 Titans were essentially average on both sides of the ball. Any improvement at all would have likely meant a postseason berth.

Instead, they finished 30th in the league and last in the AFC South in this key metric.

The collapse was similar on both offense and defense. The finished in the bottom 10 in both offensive and defensive passer ratings as they tumbled from nine wins to just six.

Defensively, the Titans improved slightly in touchdown-to-interception ratio, but saw their opponents' completion percentage rise from 62.4 to 66.3 percent and their YPA soar almost a full yard per pass.

As noted with NY/A, the Titans got more pressure on quarterbacks in 2012, but that didn't come from the front four, leaving the secondary vulnerable to big plays.

On offense, the slide can be traced to an across-the-board decline under Jake Locker. With the second-year passer guiding the offense most of the season, the Titans suffered declines in touchdown-to-interception ratio, completion percentage and most importantly, yards per attempt.

In fairness to Locker, however, Matt Hasselbeck wasn't any better during his brief tenure in the saddle.

When a team wins just six games and misses the playoffs, it's not a stretch to say that things have to get better.

The challenge for Mike Munchak comes from the fact that there wasn't any one aspect of the team he could count on in 2012.

If he's going to save his job in 2013, Tennessee will have to develop a clear identity on at least one side of the football, if not both.