As many of you know, there is a group of Footballguys, myself included, that take great pleasure in the use of statistical analysis as a means to succeed in fantasy football. Traditionally, we do much of our work leading up to the draft, using historical trends analysis and number crunching to help fine tune our annual projections for players and teams. But statistical analysis can, when used in conjunction with logical reasoning and sound football acumen, be useful during the season, as well. With that in mind, I will attempt to address some relevant in-season issues each and every week, with a statistical slant of course…

Musings on Passer Rating:

For the uninitiated, QB rating, or Passer Rating as it is more appropriately called, has long been one of the key measuring sticks by which quarterbacks are judged. Created by Don Smith, a statistician for the NFL Hall of Fame, at the request of Pete Rozelle, the passer rating was meant as a means to grade a quarterback’s performance against a normalized benchmark.

But the truth is, the passer rating was created out of necessity and unfortunately, the formula is based on quite a few arbitrary assumptions that, in my opinion, significantly flaw its value as a method of evaluating greatness, fantasy or otherwise.

From NFL.com:

“The NFL rates its passers for statistical purposes against a fixed performance standard based on statistical achievements of all qualified pro passers since 1960.

The current system, which was adopted in 1973, removes inequities that existed in the former method and, at the same time, provides a means of comparing passing performances from one season to the next.

It is important to remember that the system is used to rate passers, not quarterbacks. Statistics do not reflect running ability, leadership, play-calling, and other intangible factors that go into making a successful professional quarterback.”

Passer rating remains a commonly used benchmark for assessing the production of a quarterback. Much was made of the fact that Kurt Warner overtook Steve Young as the league’s all time highest rated passer, and therein lays the foundation for people’s argument of Warner’s greatness. And a few weeks ago, Peyton Manning was lauded for achieving a ‘perfect’ game by scoring a rating of 158.3, the highest possible under the passer rating formula.

But the real questions are, is there any value to the passer rating in evaluating “real” NFL quarterbacks or, more importantly for our discussion, the fantasy prowess of a signal caller?

Topic 1: Passer Rating and Relevance to Fantasy Football

"I pay attention to my rating on third down and in the red zone," says Trent Dilfer, who despite his wobbly 76.6 rating last season quarterbacked the Ravens to a Super Bowl victory. "Otherwise, it's most useful for fantasy football people who are more concerned with numbers than good old-fashioned winning." — GQ Magazine, October 2001

Excuse Me???? I’m a Dilfer fan, but something tells me he hasn’t the foggiest idea what we ‘fantasy football people’ care about. Give the guy credit for persevering and winning the big one, something guys like Dan Marino and Warren Moon would probably give up their places in the statistical record books to have. HOWEVER, I’m not sure there’s any basis for Trent’s assertion. Honestly, do we as fantasy football players care at all about passer rating? If anything, I would say we care LESS about the rating than football historians who use the metric as a way of quantifying the relative greatness of passers from all eras. 

So is there any obvious correlation between passer rating and fantasy effectiveness?

First of all, there is a MAJOR deficiency to the passer rating when it comes to measuring fantasy production. There is no variable that factors rushing statistics. As you all know, a few rushing touchdowns can make a big difference between a good fantasy QB and a great one. Daunte Culpepper led the league in turnovers last year (32) but finished as the top rated fantasy QB in many systems by virtue of his 10 rushing touchdowns.

Since passer rating doesn’t factor rushing statistics, we must first remove the rushing component from the QB fantasy point production in order to get an apples-to-apples correlation. Here is a list of the top rated quarterbacks, based only on passing statistics, over the last two years:

Table A: Passing Fantasy Points per Game (2001-2002, minimum of 240 attempts)

Now let’s compare each QB’s passer rating, and ranking in that category to the requisite fantasy points per game:

Table B: Passer Rating and Fantasy PPG, Ranks & Differential (2001-2002)

At first glance, there may not appear to be a strong correlation between passer rating and passing fantasy point production. For example, Tom Brady finished the 2001 season as the 6^th ranked passer, but only ranked 19^th among fantasy QBs in passing points per game. On the flip side, Aaron Brooks ranked just 20^th in rating in 2001 but was the 6^th most productive fantasy QB, in terms of passing production.

However, a closer look reveals what we already knew intuitively, that there is a strong statistical correlation between the two. In the following chart, I plotted each player’s passer rating and their passing points per game for the last two seasons. As you can see, there is a strong linear correlation between the two (R-squared = .6731).

Chart 1: Passer Rating vs. Fantasy Passing Points per Game (PPPG)

This really should not come as a surprise. After all, most fantasy leagues base point production on three things: total yardage, TD production and interceptions thrown.

Given that all three of those metrics are vital to the computation of passer rating, it stands to reason that there would be a strong linear correlation between the two. Where the passer rating differs from fantasy scoring is that it also assigns a value to HOW THE QUARTERBACKS TOTAL PRODUCTION WAS DERIVED. As fantasy owners, we really don’t care how a QB gets his points. If Jeff Garcia throws for 300 yards by completing 12 of 30 or 28 of 31, we could care less. Passer rating on the other hand assigns a much higher value to the 28 for 31.

In conclusion, while there’s strong evidence that passer rating and traditional fantasy point production are highly correlated, there is little evidence that it serves as a telling predictor of future performance. It’s not only possible, but quite common for a QB to rank in the top tier of fantasy passers while maintaining a mediocre passer rating; and vice versa.

Topic 2: Dissecting the ‘Perfect’ Rating

In Week 4, Peyton Manning had a “perfect” game according to NFL statisticians. By completing 20 of 25 pass attempts (80%) for 314 yards while throwing 6 touchdowns and no interceptions, Manning finished with a passer rating of 158.3, the highest rating allowable under the Passer Rating Formula.

Let’s first look at what constitutes a “perfect” passer rating. One of the oddities of the current passer rating formula is that a “perfect” rating equals 158.3, meaning no QB can surpass that rating regardless of his statistical feats. But did you ever wonder what hurdles a QB has to achieve to attain that rating?

• Zero interceptions
• 77.5% completion percentage or higher
• At least 11.9% TD/attempt ratio
• Yards per attempt greater than or equal to 12.5

• This was Peyton Manning’s 3^rd “perfect game” of his career; he is the active leader in that category
• Kurt Warner is the only other active player with more than one perfect game; he has two
• Since 1995, there have been nine “perfect games”

• Fran Tarkenton
• Johnny Unitas
• John Elway
• Warren Moon
• Dan Fouts

1. For more information on the subject, please check out these excellent resources on the Web: http://www.bluedonut.com/qbrating.htm and http://www.profootballhof.com/photos/All-time_Passer_Ratings.pdf
2. All fantasy point production assumes the Footballguys Scoring System: · 1 point per 25 yards passing · 1 point per 10 yards receiving or rushing · 4 points per passing TD · 6 points per rushing or receiving TD · -1 per interception thrown
3. Special thanks to Doug Drinen (www.pro-football-reference.com) and Ken Maxwell (http://www.footballguys.com/insidethestats/stats.asp) for providing the relevant statistical databases
4. Feel free to contact me ([email protected]) if you wish to discuss this column further or share other ideas for future issues