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No, Peyton, you are #1

No, Peyton, you are #1.

Back in March, Chase wrote a post investigating how quarterbacks age, finding that they peak at age 29 (with a generalized peak from 26-30) in terms of value over average. Today, I thought I’d quickly look at how quarterbacks age in terms of their performance rate — specifically, their Adjusted Net Yards per Attempt (ANY/A). For newer readers, ANY/A is based on the following formula: (Passing Yards + 20 * Passing TDs – 45 * INTs – Sack Yards Lost) / (Pass Attempts + Sacks).

First, I need to introduce a way of adjusting ANY/A for era: Relative ANY/A. Relative ANY/A is simply equal to:

QB_ANY/A – LgAvg_ANY/A

The table below lists the 30 single-season leaders in Relative ANY/A since the merger. You won’t be too surprised to see the 2004 version of Peyton Manning at the top. That year, Manning averaged 9.8 ANY/A, while the league average was just 5.6 ANY/A. That means Manning gets a Relative ANY/A grade of +4.1 (with the difference due to rounding).

RkPlayerYearAgeTeamGGSCmpAttYdsTDIntSkSkYdANY/ALgAvgANY/ARel_ANY/A
1.Peyton Manning200428clt161633649745574910131019.85.6+4.1
2.Dan Marino198423mia161636256450844817131208.95.0+3.9
3.Roger Staubach197129dal13101262111882154231757.83.9+3.9
4.Bert Jones197625clt14142073433104249292847.84.1+3.7
5.Aaron Rodgers201128gnb15153435024643456362199.45.9+3.5
6.Ken Stabler197631rai121219429127372717192037.44.1+3.4
7.John Brodie197035sfo1414223378294124108677.54.2+3.4
8.Tom Brady200730nwe16163985784806508211288.95.5+3.4
9.Randall Cunningham199835min151425942537043410201328.55.3+3.2
10.Steve Young199231sfo16162684023465257291528.14.9+3.2
11.Mark Rypien199129was1616249421356428117598.35.2+3.2
12.Kurt Warner199928ram161632549943534113292018.35.2+3.1
13.Ken Stabler197429rai141317831024692612181417.03.9+3.1
14.Steve Young199130sfo1110180279251717813798.35.2+3.1
15.Joe Montana198933sfo13132713863521268331988.35.2+3.1
16.Craig Morton197027dal12111022071819157201667.24.2+3.1
17.Dan Fouts198231sdg992043302883171112947.74.8+2.9
18.Joe Montana198428sfo161527943236302810221387.95.0+2.9
19.Ken Anderson197526cin131322837731692111322477.04.0+2.9
20.Steve Young199433sfo161632446139693510311638.25.4+2.9
21.Boomer Esiason198827cin161622338835722814302457.85.0+2.8
22.Kurt Warner200029ram111123534734292118201158.05.2+2.8
23.John Hadl197333ram141413525820082211171266.63.9+2.8
24.Peyton Manning200529clt16163054533747281017818.05.3+2.7
25.Drew Brees200930nor151536351443883411201358.35.7+2.7
26.Philip Rivers200928sdg16163174864254289251678.35.7+2.7
27.Steve McNair200330oti14142504003215247191087.85.2+2.6
28.Brian Griese200025den10102163362688194171397.85.2+2.6
29.Peyton Manning200630clt1616362557439731914867.95.4+2.5
30.Tom Brady201033nwe16163244923900364251758.25.7+2.5

Using this, we can evaluate every quarterback’s season independently of era, and compute the year-to-year differences in Relative ANY/A at every age.

Taking every quarterback who had at least 15.1 dropbacks per game (which tends to correspond to the standard 14 attempts per team game) in back to back seasons, I fed the year-to-year Relative ANY/A deltas into a cubic regression and smoothed out an aging curve. (This is the same process I used to calculate an aging curve for basketball players for ESPN Insider last year.)

According to this methodology, here’s how a QB can expect his Relative ANY/A to change from year to year at each age:

From AgeTo AgeDelta
2021+0.88
2122+0.66
2223+0.47
2324+0.32
2425+0.20
2526+0.10
2627+0.02
2728-0.04
2829-0.08
2930-0.11
3031-0.14
3132-0.15
3233-0.17
3334-0.19
3435-0.21
3536-0.24
3637-0.28
3738-0.33
3839-0.40
3940-0.50
4041-0.61
4142-0.76

Or in graphic form:

ANY-A by year

This would indicate that on average, quarterbacks peaks at age 27. To put the data in another light, if we created a passer who peaked at 8.0 ANY/A, and he perfectly followed this age curve, here is how his ANY/A would look each season:

ANY-A progression

One big caveat with this study: there’s probably a good deal of selection bias here, in the sense that only passers deemed to be good enough to keep playing will get a chance to put up 15.1 dropbacks/game the following year. Still, I think this provides a pretty good estimate of how much improvement/decline you can expect from a guy at a given age.

Armed with this aging curve, we can do a lot of cool things in subsequent posts, so stay tuned….