Peyton Manning has an amazing 134.7 passer rating after three games. Of course, passer rating is generally silly statistic, but I like it, in large part BECAUSE of its silliness. You can have all sorts of fun playing around with the numbers. This post, for instance, was just going to be a short one about Peyton Manning’s passer rating. Instead it expanded a bit to talk about the yin and the yang of playing quarterback.Don Smith invented the first passer rating in 1971, and it has been tinkered with quite a bit since. You probably know that college football and the NFL have two different methods for figuring passer rating -- we’re going to go with the NFL model because the point here is Peyton Manning. Maybe well mess around with college quarterback rating some other day.Here are two basic things to know about passer rating.1. Though it’s a slightly complicated formula, the general point is is that it adds together completion percentage, yards per attempt, touchdowns per attempt and subtracts interceptions per attempt. Those are the four sections of passer rating -- nothing else is involved. Sacks don’t matter. Wins don’t matter. Dropped balls don’t matter. Pressure performance doesn’t matter.2. There is a ceiling on how high a passer rating can go. I remember thinking this was kind of crazy, but I’m told there are real mathematical reasons for this ceiling. Anyway, the highest possible passer rating is 158.3. We will refer to that as the perfect passer rating (PPR) though, of course, it isn’t really perfect. You don’t have to complete 100% of your passes or throw a touchdown pass on every play to get a perfect passer rating. No, here’s what you need to do:-- Complete 77.5% of your passes.-- Get 12.5 yards per attempt.-- Get a touchdown on 11.875% of your passes (roughly one out of every 8.4 passes)-- Throw zero interceptions, obviously.Going back to 1960, only 10 quarterbacks have thrown 25 passes in a game and finished with a perfect quarterback rating. Only one quarterback has done if more than once -- that is Tom Brady who did it at Miami in 2007 and at Detroit in 2010. In the Miami game he went 21 for 25 with 354 yards and six touchdowns. In the Detroit one, he went 21 of 27 for 341 yards and four touchdowns. Impressive.The other nine quarterbacks deserve mention here:-- Ken O’Brien at Seattle in 1986: 26 of 32, 431 yards, 4 touchdowns.-- Dave Krieg against Buffalo in 1994: 20-25, 351 yards, 3 touchdowns.-- Chris Chandler at Cincinnati in 1995: 23 of 26, 352 yards, 4 touchdowns.(I was at this game … it was an impressive blend of great passing and horrendous Bengals defense)-- Doug Flutie at Seattle in 2000: 20 of 25, 366 yards, 3 touchdowns.-- Kurt Warner against San Diego in 2000: 24 of 30, 390 yards, 4 touchdowns.-- Kerry Collins at Indianapolis in 2002: 23 of 29, 366 yards, 4 touchdowns.-- Trent Green against Detroit in 2003: 20 of 25, 341 yards, 3 touchdowns(I was at this game too, in fact I was figuring his QB rating while the game was going on to see if he would hit the perfect number. That Chiefs offense, with Green and Priest Holmes and Tony Gonzalez and an amazing offensive line, was something else).-- Peyton Manning at New Orleans in 2003: 20 of 25, 314 yards, 6 touchdowns.-- Donovan McNabb against Detroit in 2007: 21 of 26, 381 yards, 4 touchdowns.Anyway, I was curious -- this year, how close is Peyton Manning to perfect? Well, here are Peyton Manning’s numbers against the perfect passer rating:Completion percentage: Manning 73%, PPR 77.5%Yards per attempt: Manning 9.4, PPR 12.5Touchdowns per attempt: Manning 9.84%, PPR 11.875%Interception percentage: Manning 0%, PRR 0%.So, for Manning to have been perfect, he needed to complete six more passes, gain 377 more yards and throw two more touchdown passes. The yardage is obviously the biggest difference. And it leads to this: Yards per attempt is a fascinating little statistic. On the surface, it seems to be about throwing the ball downfield. But it isn’t, not exactly.As you no doubt know, quarterbacks used to throw the ball downfield much more boldly. The game was different. Quarterbacks dropped back seven yards, nine yards, 11 yards and they flung the ball down the field. This is perhaps best seen in yards per COMPLETION (not attempt). There have been 47 quarterbacks in pro football history who have averaged 17 or more yards per completion over a season (min. 1,000 yards passing). Not one of those 47 has played in the 25 seasons. Joe Namath in his amazing 1967 season averaged 15.5 yards per pass completion.Dan Marino in his amazing 1984 season averaged 14.0 yards per pass completion.Tom Brady in his amazing 2007 season averaged 12.1 yards per pass completion.This is a different style of play. Namath threw the ball downfield with abandon. That was the style of his day. He knew that he would not complete a high percentage of his passes and he didn’t (over his career he barely hit half his passes). He knew that he would throw a lot of interceptions and he did (he threw 220 of them against only 173 touchdown passes in his career). This was what coaches wanted. This was what teams did. I guess I can best compare it to the game of low-OBP sluggers of the 1970s and 1980s like Andre Dawson and Steve Garvey who say they were told to sacrifice batting average and on-base percentage in order to produce runs. Maybe today’s knowledge invalidates the strategy, but it was a different time.By the time of Marino, quarterbacks were not quite so capricious -- they completed a higher percentage of passes and were definitely expected to throw fewer interceptions than touchdown passes. Still, it was looser than it is now. Marino threw the ball downfield with good accuracy (64% completion percentage) and everyone accepted the 17 interceptions that came with that.But in Brady’s time, in Manning’s time, in Aaron Rodgers’ time … perfection is the goal. Nothing less. No interceptions. As few incompletions as possible. In 2007, Brady threw 50 touchdown passes and for 4,806 yards.He completed more than 68% of his passes. He threw only eight interceptions. This is how the great quarterbacks are expected to play now, with no mistakes and, along with that, no undue risk.This is why pass per attempt is so interesting. Because while Darryl Lamonica in 1964 averaged an unbelievable 20.7 yards per completion, he averaged a good-but-not-record-breaking 8.9 yards per attempt. Lamonica was called the mad bomber and when those bombs landed, absolutely, it was a huge play. But considering that he hit 43% of his passes that year and threw eight interceptions vs. six touchdown passes you realize that was were more “mad” than “bomb.”Then you look at Kurt Warner in 2000. He hit 14.6 yards per completion, which is certainly high but not anywhere near Lamonica or Namath’s best. But because Warner was so accurate (he hit 68% of his passes), his 9.9 yards per attempt is the highest ever for a quarterback who threw more than 300 passes in a season. Highest yards per attempt (min. 300 passes)1. Kurt Warner, 2000, 9.92. Chris Chandler, 1998, 9.63. John Unitas, 1964, 9.34. Aaron Rodgers, 2011, 92.5. Lynn Dickey, 1983, 9.26. Boomer Esiason, 1988, 9.27. Earl Morrall, 1968, 9.28. Peyton Manning, 2004, 9.29. Joe Montana, 1989, 9.210. Bert Jones, 1976, 9.0So, the list is a blend of old quarterbacks who threw downfield a bit more and modern quarterbacks who generally tend to play more for completions. And that’s the yin and yang of quarterbacking. Throw downfield at risk of incompletions and interceptions. Play safer with short passes and cut severely into your yardage.And so where does it lead. Well, when you look at passer rating, I would say it is possible -- it hasn’t happened and probably won’t, but it’s POSSIBLE -- to complete 77.5% of your passes over a season and hit perfection on the rating.I would say it is possible to have an 11.875% touchdown percentage. It hasn’t happened since Sid Luckman threw 28 touchdown passes in just 202 attempts in 1943. But it’s possible.I would say it is even possible to go a whole season without throwing an interception. You would need a lot of luck as well as a lot of skill, but hey, in 2006 Damon Huard threw 244 passes and only one interception. And he’s Damon Huard.But I don’t think it’s possible to to get 12.5 yards per pass attempt over a whole season. There are too many variables at work. I think no matter how well he plays, Peyton Manning is destined to fall a little bit shy of perfection.