SITE NEWS: We are moving all of our site and company news into a single blog for Sports-Reference.com. We'll tag all PFR content, so you can quickly and easily find the content you want.

Also, our existing PFR blog rss feed will be redirected to the new site's feed.

Pro-Football-Reference.com ยป Sports Reference

For more from Chase and Jason, check out their work at Football Perspective and The Big Lead.

Super Bowl Winners, SRS champs, ANY/A and AYPC

Posted by Chase Stuart on January 16, 2009

I don't think this post will shed any light for our regular PFR readers, but I propose that from now on, we rank passing offenses not by passing yards but by either adjusted net yards per attempt or by Value - the number of adjusted yards gained over the league average.

Adjusted net yards per attempt, of course, is calculated by adding 20 yards (previously 10 yards) for each passing touchdown, subtracting 45 yards for each interception, subtracting sack yards from gross passing yards, and dividing this adjusted yardage by the combined number of sacks and attempts. That gives you the adjusted net yards per attempt for every player or team. To get their Value, you would subtract the league average from that number and multiply the difference by their number of combined sacks and pass attempts.

To me, this is a much better way to rank team passing. For example,

the 2008 Rams passed for 2,947 yards while the Titans passed for 2,819 yards. But along with those numbers, the Rams had 11 TD passes, 19 INTs, 520 attempts and were sacked 45 times. The Titans had 13 TD throws, 11 INTs, 453 attempts and were only sacked twelve times. The Rams averaged 4.09 ANY/A while the Titans averaged 5.75 adjusted net yards per attempt. With a league-wide average of 5.70 ANY/A, that puts the Rams at -911 yards above average (Value) and the Titans at 23 yards of Value. So despite St. Louis ranking ahead of Tennessee in passing yards, it seems obvious to me the the Titans were the far superior passing team.

While ranking passing teams by ANY/A or by Value makes good theoretical sense, there are many ways to test whether or not our theory holds water. While this isn't the most decisive way to do so, a timely and interesting way would be to measure how past Super Bowl winners rank in passing yards, adjusted net yards per attempt, and Value.

            PYD   ANY/A  VALUE
gnb1966     12     1      1
gnb1967     16    12     12
nyj1968      3     4      2
kan1969     16    12     12
clt1970      3     7      5
dal1971      2     1      1
mia1972     16     1      1
mia1973     21     7     10
pit1974     21    17     17
pit1975     14     5      5
rai1976      3     2      2
dal1977      4     1      1
pit1978     12     2      3
pit1979      2     3      4
rai1980     19    18     17
sfo1981      7     5      4
was1982     12     5      5
rai1983      9    11      9
sfo1984      4     2      2
chi1985     20     6      6
nyg1986     17    12     12
was1987      4     3      3
sfo1988     10     6      6
sfo1989      2     1      1
nyg1990     22     5      6
was1991      5     1      1
dal1992      5     3      3
dal1993      7     2      2
sfo1994      4     1      1
dal1995     13     4      5
gnb1996      5     1      1
den1997      9     3      3
den1998      7     3      4
ram1999      1     1      1
rav2000     22    23     23
nwe2001     22    11     11
tam2002     15    15     15
nwe2003      9    10      9
nwe2004     11     7      7
pit2005     24     7      8
clt2006      2     1      1
nyg2007     21    22     23
average     10.8   6.3    6.3

This supports the argument that ANY/A is a better at predicting future success than passing yards. The average Super Bowl champion ranked 11th in the league in raw passing yards but sixth once you start making some adjustments. The 1990 Giants and '05 Steelers are good examples of this. Those teams didn't pass often but when they did, they passed efficiently. The '90s Cowboys were good passing teams that simply didn't throw that often; but we saw in the playoffs that they could throw when they needed to. Those were great passing teams by ANY/A standards, and considering their talent, ANY/A does a much better job than raw passing yards. So we can have some confidence that for predictive purposes, we'd care a lot more about a team's ANY/A or Value than their raw passing yards.

We can also measure whether this method is better at rating team accomplishments -- i.e., a retrodictive system. I looked at the best team in the NFL each year (as measured by SRS) and checked their rankings in the same three categories. Note: While PFR hasn't run the 2008 SRS numbers yet, I suspect the Titans will come in at #1, further supporting the use of ANY/A over raw passing yards.

            PYD   ANY/A  VALUE
nwe2007      1     1      1
nwe2006     12     9      8
clt2005      3     1      1
nwe2004     11     7      7
kan2003      2     4      4
rai2002      1     2      1
ram2001      1     1      1
rai2000     15     6      7
ram1999      1     1      1
min1998      1     1      1
den1997      9     3      3
gnb1996      5     1      1
sfo1995      1     5      4
sfo1994      4     1      1
sfo1993      2     1      1
sfo1992      3     1      1
was1991      5     1      1
buf1990     10     2      3
sfo1989      2     1      1
min1988      4     4      5
sfo1987      2     1      1
nyg1986     17    12     12
chi1985     20     6      6
sfo1984      4     2      2
was1983      7     1      1
nyj1982      7     4      4
phi1981     20    14     13
phi1980      7     1      2
pit1979      2     3      4
dal1978      3     1      1
den1977     18     7      8
pit1976     22    13     13
pit1975     14     5      5
was1974      1     1      1
ram1973     13     1      2
mia1972     16     1      1
clt1971     21    19     20
min1970     14    10     11
average      7.9  4.1     4.2

Once again, the adjusted versions come out on top.

You can do the same exact analysis for pass defense. Here are the rankings of the SB champs:

            PYD   ANY/A  VALUE
gnb1966      1     1      1
gnb1967      1     1      1
nyj1968      7     5      6
kan1969      5     2      2
clt1970     21     4      4
dal1971     19     6      5
mia1972      5     1      2
mia1973      1     2      2
pit1974      1     1      1
pit1975      4     3      3
rai1976     23    18     18
dal1977      2     2      2
pit1978     12     4      4
pit1979     10     4      3
rai1980     19     5      5
sfo1981      3     3      3
was1982      7    11     11
rai1983     13     9      9
sfo1984     17     9      9
chi1985      3     1      1
nyg1986     19     7      5
was1987     24     9      9
sfo1988      8     8      6
sfo1989     11     6      6
nyg1990      6     3      3
was1991      9     3      3
dal1992      5    10      9
dal1993     10    10     11
sfo1994     17     5      5
dal1995      8     9      9
gnb1996      1     1      1
den1997      5     4      5
den1998     26    14     14
ram1999     20     3      3
rav2000      8     4      5
nwe2001     24    13     13
tam2002      1     1      1
nwe2003     15     1      1
nwe2004     17     8      7
pit2005     16     5      4
clt2006      2     9     12
nyg2007     11    12     12
average     10.4   5.6    5.6

And the SRS champs:

            PYD   ANY/A  VALUE
nwe2007      6     5      6
nwe2006     12     3      3
clt2005     15    10      9
nwe2004     17     8      7
kan2003     20     4      4
rai2002     23    10      9
ram2001     11     4      4
rai2000     25    15     14
ram1999     20     3      3
min1998     19     8      7
den1997      5     4      5
gnb1996      1     1      1
sfo1995     11     1      1
sfo1994     17     5      5
sfo1993     16     8      6
sfo1992     26    16     16
was1991      9     3      3
buf1990      7     8      9
sfo1989     11     6      6
min1988      2     1      1
sfo1987      1     1      1
nyg1986     19     7      5
chi1985      3     1      1
sfo1984     17     9      9
was1983     28    14     14
nyj1982      9     4      2
phi1981      1     1      1
phi1980      5     4      2
pit1979     10     4      3
dal1978      5     5      5
den1977     25     8      6
pit1976      6     6      4
pit1975      4     3      3
was1974      5     2      2
ram1973      7     5      7
mia1972      5     1      2
clt1971      2     1      2
min1970      1     1      1
average     11.2   5.3    5.0

There is little benefit in calling a team a good passing team based on their raw passing yards -- we really should just use their Value or their ANY/A numbers. Similar, a team's pass defense must be measured by ANY/A or Value, as raw passing yards allowed doesn't tell a great story.

All that said, what do the 2008 numbers look like?

Tm                      ANY/A    Value
San Diego Chargers      8.04     1174
New Orleans Saints      7.47     1145
Arizona Cardinals       7.02      866
Miami Dolphins          7.19      768
Indianapolis Colts      6.83      677
Atlanta Falcons         7.01      589
Denver Broncos          6.58      556
Green Bay Packers       6.59      508
Carolina Panthers       6.72      443
Houston Texans          6.45      439
New York Giants         6.14      227
New England Patriots    6.00      174
Dallas Cowboys          6.00      172
Philadelphia Eagles     5.80       63
Tennessee Titans        5.75       22
Tampa Bay Buccaneers    5.71        6
Baltimore Ravens        5.55    -  70
Washington Redskins     5.54    -  91
Pittsburgh Steelers     5.42    - 160
Minnesota Vikings       5.32    - 192
Jacksonville Jaguars    5.26    - 256
San Francisco 49ers     5.22    - 273
Buffalo Bills           5.12    - 304
Chicago Bears           5.08    - 346
Kansas City Chiefs      4.96    - 428
New York Jets           4.84    - 480
Oakland Raiders         4.64    - 490
Seattle Seahawks        4.51    - 607
Detroit Lions           4.39    - 735
St. Louis Rams          4.09    - 911
Cleveland Browns        3.32    -1220
Cincinnati Bengals      3.46    -1266

I think the 2009 Jets will manage to get along just fine without Brett Favre. And it's no surprise that seven of the bottom eight teams in passing Value will be making the first seven pick in this April's draft.

I did the same analysis for team rushing but got different results. I used rushing yards, adjusted yards per carry (yards per carry but with a 20-yard bonus for a rushing TD), adjusted yards per carry over 3.5 yards per carry and AYPC over 3.0 YPC. All those formulas produced similar results - the SB champion and the SRS champion averaged between an 8 and 10 ranking on all metrics. I suspect that a better analysis would be to just use the RBs for the team, because team rushing is much more likely to be influenced inappropriately than team passing -- QB kneeldowns, QB scrambles and reverses happen relatively frequently.

That said, there's a key distinction between rushing and passing. Allow me to make some gross generalizations. When you're a good passing team (measured by ANY/A), you probably won't need to pass that often. You'll score points and you'll be winning, so you'll stop throwing. If you're a bad passing team, you'll throw some INTs, have a bunch of three and outs, and are likely to have to pass a bunch in the fourth quarter. That's exactly why raw passing yards is a bad way to measure passing production -- bad passing teams are likely to have a bunch of passing yards late in the game and good passing teams aren't going to accumulate many passing yards at the ends of games. That means passing yards doesn't accurately measure passing ability, since it penalizes good passing teams and helps bad passing teams.

The opposite happens with rushing. If you're a great rushing team, you'll keep rushing. If you're a bad rushing team, you'll stop rushing. If you're effective running the ball through three quarters, you may not average a high YPC in the fourth quarter, but you'll keep running. If you've got 14 carries for 42 yards after three quarters and are down by 10 points, you're unlikely to have a 100 yard day. So in that sense, raw rushing yards tells a pretty good story. And that's why raw rushing yards and adjusted yards per carry over 3.0 YPC won't bring out too many differences. While I might have a slight preference for AYPC over 3.5 or 3.0 yards per carry, rushing yards hits the nail pretty well (especially if you just use rushing yards by running backs).

This entry was posted on Friday, January 16th, 2009 at 8:28 am and is filed under History, Statgeekery. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.