Guest Post: Marginal Yards After the Catch, Part II

by Chase Stuart on October 20, 2014

In early September, Adam Steele, a longtime reader and commenter known by the username “Red” introduced us to his concept of Marginal Yards after the Catch. Today is Part II to that post. Adam lives in Superior, Colorado and enjoys digging beneath quarterback narratives to discover the truth; hey, who can blame him?

Introducing Marginal Air Yards

There are three components of Y/A: Completion %, Air Yards/Completion, and YAC/Completion. In my last post I looked at YAC, so today, let’s look at the other two components. By multiplying completion percentage and air yards per completion, we get air yards per attempt, which we can then modify to create Marginal Air Yards (mAir):

mAir = (Air Yards/Attempt – LgAvg Air Yards/Attempt)*Attempts

Here are the yearly Air Yard rates since 1992, with the table sorted by Air Yards per Attempt::

#	Year	Att	Comp	Yards	AirYds	Com %	Air/C	Air/A	Air %
1	2004	16354	9772	115338	68084	59.8%	6.967	4.163	59%
2	1992	13408	7705	92011	55166	57.5%	7.16	4.114	60%
3	1998	15489	8766	106086	62214	56.6%	7.097	4.017	58.6%
4	1993	14414	8351	96490	56810	57.9%	6.803	3.941	58.9%
5	1997	15729	8844	105288	61314	56.2%	6.933	3.898	58.2%
6	2005	16464	9790	111721	64167	59.5%	6.554	3.897	57.4%
7	2007	17045	10425	116874	65810	61.2%	6.313	3.861	56.3%
8	2011	17410	10464	125330	67201	60.1%	6.422	3.86	53.6%
9	2012	17788	10833	125951	68380	60.9%	6.312	3.844	54.3%
10	2001	16181	9542	109639	62083	59%	6.506	3.837	56.6%
11	1999	16760	9567	113254	64172	57.1%	6.708	3.829	56.7%
12	1994	15056	8739	101884	57614	58%	6.593	3.827	56.5%
13	1995	16699	9717	113069	63825	58.2%	6.568	3.822	56.4%
14	2000	16322	9497	110131	62356	58.2%	6.566	3.82	56.6%
15	2002	17292	10314	116201	65578	59.6%	6.358	3.792	56.4%
16	2008	16526	10081	114766	62520	61%	6.202	3.783	54.5%
17	2006	16389	9796	112277	61920	59.8%	6.321	3.778	55.1%
18	1996	15966	9198	106661	60264	57.6%	6.552	3.775	56.5%
19	2003	16493	9695	109467	61705	58.8%	6.365	3.741	56.4%
20	2010	17269	10491	120964	63917	60.8%	6.093	3.701	52.8%
21	2013	18136	11102	129177	67006	61.2%	6.035	3.695	51.9%
22	2009	17033	10372	118917	62439	60.9%	6.02	3.666	52.5%

Air Yards/Attempt have remained fairly constant over the years, despite the substantial increase in overall passing efficiency in recent seasons. The boosted efficiency of today’s passing game is almost entirely a result of increases in YAC and decreases in INT %; completion % has also steadily risen over the years, but it’s balanced out by a large decrease in Air Yards/Completion. In fact, the average depth of completions has fallen more than a full yard (7.16 to 6.04) since 1992. However, it’s interesting to note that 2004 saw a major spike in Air Yards/Completion, which just happens to be the last time illegal contact penalties were re-emphasized (we’ll have to revisit this topic once the 2014 season is in the books).

Now, let’s look at the top 50 seasons of Marginal Air Yards since 1992.

#	QB	Year	Team	Att	Comp	Yards	AirYds	Com %	Air/C	Air/A	Air %	mAir
1	Daunte Culpepper	2000	MIN	474	297	3937	2621	62.7%	8.8	5.5	66.6%	810
2	Peyton Manning	2006	IND	557	362	4397	2889	65%	8	5.2	65.7%	785
3	Mark Brunell	1996	JAC	557	353	4367	2885	63.4%	8.2	5.2	66.1%	782
4	Peyton Manning	2004	IND	497	336	4557	2832	67.6%	8.4	5.7	62.1%	763
5	Steve McNair	2003	TEN	400	250	3215	2198	62.5%	8.8	5.5	68.4%	702
6	Kurt Warner	2001	STL	546	375	4830	2760	68.7%	7.4	5.1	57.1%	665
7	Peyton Manning	2000	IND	571	357	4413	2835	62.5%	7.9	5	64.2%	654
8	Steve McNair	2001	TEN	431	264	3350	2303	61.3%	8.7	5.3	68.7%	649
9	Jeff Hostetler	1993	RAI	419	236	3242	2250	56.3%	9.5	5.4	69.4%	599
10	Tony Romo	2006	DAL	337	220	2903	1850	65.3%	8.4	5.5	63.7%	577
11	Tom Brady	2007	NE	578	398	4806	2787	68.9%	7	4.8	58%	555
12	Randall Cunningham	1998	MIN	425	259	3704	2259	60.9%	8.7	5.3	61%	552
13	Chris Chandler	1998	ATL	327	190	3154	1858	58.1%	9.8	5.7	58.9%	544
14	Peyton Manning	2005	IND	453	305	3747	2309	67.3%	7.6	5.1	61.6%	544
15	Aaron Rodgers	2011	GB	502	343	4643	2480	68.3%	7.2	4.9	53.4%	542
16	Carson Palmer	2006	CIN	520	324	4035	2503	62.3%	7.7	4.8	62%	538
17	Jeff George	1999	MIN	329	191	2816	1788	58.1%	9.4	5.4	63.5%	528
18	Ben Roethlisberger	2009	PIT	506	337	4328	2376	66.6%	7.1	4.7	54.9%	521
19	Kurt Warner	2000	STL	347	235	3429	1843	67.7%	7.8	5.3	53.7%	517
20	Peyton Manning	2007	IND	515	337	4040	2497	65.4%	7.4	4.8	61.8%	509
21	Matt Hasselbeck	2005	SEA	449	294	3459	2256	65.5%	7.7	5	65.2%	506
22	Eli Manning	2011	NYG	589	359	4933	2758	61%	7.7	4.7	55.9%	484
23	Tony Romo	2007	DAL	520	335	4211	2492	64.4%	7.4	4.8	59.2%	484
24	Trent Green	2000	STL	240	145	2063	1400	60.4%	9.7	5.8	67.9%	483
25	Scott Mitchell	1995	DET	583	346	4338	2710	59.3%	7.8	4.6	62.5%	482
26	Drew Brees	2009	NO	514	363	4388	2349	70.6%	6.5	4.6	53.5%	465
27	Jake Delhomme	2008	CAR	414	246	3288	2019	59.4%	8.2	4.9	61.4%	453
28	Drew Bledsoe	1998	NE	481	263	3633	2379	54.7%	9	4.9	65.5%	447
29	John Elway	1998	DEN	356	210	2806	1875	59%	8.9	5.3	66.8%	445
30	Carson Palmer	2005	CIN	509	345	3836	2428	67.8%	7	4.8	63.3%	444
31	Ben Roethlisberger	2007	PIT	404	264	3154	1999	65.3%	7.6	4.9	63.4%	439
32	Elvis Grbac	2000	KC	547	326	4169	2525	59.6%	7.7	4.6	60.6%	435
33	Ben Roethlisberger	2004	PIT	295	196	2621	1662	66.4%	8.5	5.6	63.4%	434
34	Drew Brees	2011	NO	657	468	5476	2965	71.2%	6.3	4.5	54.1%	429
35	Eli Manning	2012	NYG	536	321	3948	2487	59.9%	7.7	4.6	63%	427
36	Steve Young	1993	SF	462	314	4023	2247	68%	7.2	4.9	55.9%	426
37	Philip Rivers	2009	SD	486	317	4254	2206	65.2%	7	4.5	51.9%	424
38	Peyton Manning	2012	DEN	583	400	4659	2665	68.6%	6.7	4.6	57.2%	424
39	Jim Kelly	1992	BUF	462	269	3457	2322	58.2%	8.6	5	67.2%	421
40	Steve Beuerlein	1993	PHO	418	258	3164	2068	61.7%	8	4.9	65.4%	421
41	Matt Schaub	2009	HOU	583	396	4770	2550	67.9%	6.4	4.4	53.5%	413
42	Marc Bulger	2004	STL	485	321	3964	2429	66.2%	7.6	5	61.3%	410
43	Dan Marino	1992	MIA	554	330	4116	2687	59.6%	8.1	4.9	65.3%	408
44	Mark Brunell	2000	JAC	512	311	3640	2358	60.7%	7.6	4.6	64.8%	402
45	Matt Ryan	2008	ATL	434	265	3440	2036	61.1%	7.7	4.7	59.2%	394
46	Mark Brunell	2001	JAC	473	289	3309	2205	61.1%	7.6	4.7	66.6%	390
47	Tom Brady	2004	NE	474	288	3692	2363	60.8%	8.2	5	64%	390
48	Marc Bulger	2003	STL	532	336	3845	2375	63.2%	7.1	4.5	61.8%	385
49	Tommy Maddox	2002	PIT	377	234	2836	1813	62.1%	7.7	4.8	63.9%	383
50	Steve Young	1992	SF	402	268	3465	2035	66.7%	7.6	5.1	58.7%	381

This list represents nearly all of the greatest QB seasons of the last two decades, and not a single season that would be considered below average. It makes sense that quarterbacks would have more control over Air Yards than YAC, because Air Yards are created with the ball in the QB’s hands, while YAC happens in the receiver’s hands. However, there seems to be one glaring exception to that rule, and his name is Randy Moss. Four of the top 20 mAir seasons have occurred with Moss as the #1 receiver, and represent by far the best mAir seasons for each of his quarterbacks (Culpepper, Brady, Cunningham, and George). This doesn’t move Moss ahead of Jerry Rice for the GOAT title, but in my opinion it builds on Neil’s work and definitely moves him closer.

Setting aside the Randy Effect, Peyton Manning is the undisputed King of Air Yards during this era. He’s registered six seasons in the top 50, while nobody else has more than three. Somewhat surprisingly, Mark Brunell makes three appearances here. We forget about him because he played in Jacksonville and never reached the Super Bowl, but the Coughlin-era Jaguars had a potent passing attack, and Brunell was doing the lion’s share of the work with his excellent downfield throws. If you ignore RINGZ theory, Brunell ran Coughlin’s offense much better than Eli Manning ever has. The most prolific aerial attack of the last two decades is not immediately obvious, because it was spilt between Kurt Warner and Trent Green. The 2000 Rams totaled exactly +1000 Marginal Air Yards, which essentially laps the field (there are only eight other seasons above 600 mAir). Remember, that team went 10-6 despite finishing dead last in scoring defense. Greatest Show on Turf indeed.

What about the worst QB’s at producing Air Yards? Here are the bottom 50:

#	QB	Team	Year	Att	Comp	Yards	AirYds	Com %	Air/C	Air/A	Air %	mAir
965	Christian Ponder	MIN	2012	483	300	2935	1222	62.1%	4.1	2.5	41.6%	-635
964	Mark Rypien	WAS	1993	319	166	1514	623	52%	3.8	2	41.1%	-634
963	Sam Bradford	STL	2010	590	354	3512	1570	60%	4.4	2.7	44.7%	-614
962	Joey Harrington	DET	2003	554	309	2880	1467	55.8%	4.7	2.6	50.9%	-606
961	Blaine Gabbert	JAC	2011	413	210	2214	1033	50.8%	4.9	2.5	46.7%	-561
960	Joey Harrington	DET	2004	489	274	3047	1477	56%	5.4	3	48.5%	-559
959	Brett Favre	GB	2006	613	343	3885	1764	56%	5.1	2.9	45.4%	-552
958	Boomer Esiason	CIN	1992	278	144	1407	646	51.8%	4.5	2.3	45.9%	-498
957	Tom Brady	NE	2002	601	373	3764	1782	62.1%	4.8	3	47.3%	-497
956	Joey Harrington	DET	2002	429	215	2294	1130	50.1%	5.3	2.6	49.3%	-497
955	Brett Favre	GB	1993	522	318	3303	1568	60.9%	4.9	3	47.5%	-489
954	Bruce Gradkowski	TB	2006	328	177	1661	750	54%	4.2	2.3	45.2%	-489
953	Donovan McNabb	PHI	2000	569	330	3365	1686	58%	5.1	3	50.1%	-488
952	Matt Hasselbeck	SEA	2009	488	293	3029	1304	60%	4.5	2.7	43.1%	-485
951	Chad Henne	JAC	2013	503	305	3241	1378	60.6%	4.5	2.7	42.5%	-481
950	Brandon Weeden	CLE	2012	517	297	3385	1514	57.4%	5.1	2.9	44.7%	-473
949	David Carr	HOU	2006	442	302	2767	1198	68.3%	4	2.7	43.3%	-472
948	Bobby Hoying	PHI	1998	224	114	961	432	50.9%	3.8	1.9	45%	-468
947	Chris Weinke	CAR	2001	540	293	2931	1614	54.3%	5.5	3	55.1%	-458
946	Drew Bledsoe	NE	2000	531	312	3291	1574	58.8%	5	3	47.8%	-454
945	Kyle Boller	BAL	2004	464	258	2559	1498	55.6%	5.8	3.2	58.5%	-434
944	Ryan Fitzpatrick	BUF	2012	505	306	3400	1514	60.6%	4.9	3	44.5%	-427
943	David Klingler	CIN	1993	343	190	1935	926	55.4%	4.9	2.7	47.9%	-426
942	Drew Brees	SD	2003	356	205	2108	927	57.6%	4.5	2.6	44%	-405
941	Jason Campbell	WAS	2009	507	327	3618	1457	64.5%	4.5	2.9	40.3%	-402
940	Alex Smith	KC	2013	508	308	3313	1478	60.6%	4.8	2.9	44.6%	-399
939	Jimmy Clausen	CAR	2010	299	157	1558	713	52.5%	4.5	2.4	45.8%	-394
938	Shaun Hill	DET	2010	416	257	2686	1152	61.8%	4.5	2.8	42.9%	-388
937	Steve Bono	KC	1996	438	235	2572	1273	53.7%	5.4	2.9	49.5%	-380
936	Drew Bledsoe	NE	1995	636	323	3507	2055	50.8%	6.4	3.2	58.6%	-376
935	Matt Cassel	NE	2008	516	327	3693	1577	63.4%	4.8	3.1	42.7%	-375
934	Ryan Fitzpatrick	BUF	2011	569	353	3832	1836	62%	5.2	3.2	47.9%	-360
933	Philip Rivers	SD	2012	527	338	3606	1667	64.1%	4.9	3.2	46.2%	-359
932	Jason Campbell	WAS	2008	506	315	3245	1559	62.3%	4.9	3.1	48%	-355
931	Matthew Stafford	DET	2009	377	201	2267	1031	53.3%	5.1	2.7	45.5%	-351
930	Ryan Fitzpatrick	CIN	2008	372	221	1905	1057	59.4%	4.8	2.8	55.5%	-350
929	Jon Kitna	SEA	2000	418	259	2658	1247	62%	4.8	3	46.9%	-350
928	Peyton Manning	IND	1998	575	326	3739	1965	56.7%	6	3.4	52.6%	-345
927	Stan Gelbaugh	SEA	1992	255	121	1307	710	47.5%	5.9	2.8	54.3%	-339
926	Kyle Boller	STL	2009	176	98	899	307	55.7%	3.1	1.7	34.1%	-338
925	Shane Matthews	CHI	1999	275	167	1645	723	60.7%	4.3	2.6	44%	-330
924	Jim Miller	CHI	2001	395	228	2299	1187	57.7%	5.2	3	51.6%	-329
923	Boomer Esiason	NYJ	1994	440	255	2782	1356	58%	5.3	3.1	48.7%	-328
922	Brad Johnson	MIN	2006	439	270	2750	1331	61.5%	4.9	3	48.4%	-328
921	Brett Favre	GB	1994	582	363	3882	1906	62.4%	5.3	3.3	49.1%	-321
920	Donovan McNabb	PHI	1999	216	106	948	506	49.1%	4.8	2.3	53.4%	-321
919	Josh Freeman	TB	2011	551	346	3592	1806	62.8%	5.2	3.3	50.3%	-321
918	Bubby Brister	NYJ	1995	170	93	726	330	54.7%	3.5	1.9	45.5%	-320
917	Koy Detmer	PHI	1998	181	97	1011	410	53.6%	4.2	2.3	40.6%	-317
916	Drew Brees	SD	2002	526	320	3284	1678	60.8%	5.2	3.2	51.1%	-317

A quick perusal of this list reveals the validity of Marginal Air Yards in measuring a quarterback’s contribution (or lack thereof) to his passing offense. The worst mAir seasons are basically a who’s who of impotent quarterbacking, with names like Harrington, Campbell, Fitzpatrick, and Boller making multiple appearances. However, there are a few shockers, most notably Brett Favre showing up three times. Despite his reputation as a wild gunslinger, he was actually a Captain Checkdown for a good portion of his career. Favre’s total career mAir is a dizzying -1335, ahead of only David Carr and Joey Harrington. I did NOT see that coming. The other QB who underthrows his reputation is Donovan McNabb, posting two seasons in the bottom 50 and a career total of -1223. I had always thought of McNabb as a guy who completed plenty of deep passes to counterbalance his low completion %, but apparently that was not the case. He really padded his stats with all those screen passes to Brian Westbrook, and it makes his historically low INT % look less impressive (although low Air Yards didn’t help Favre avoid INT’s).

Do Air Yards affect YAC?

Before I started crunching numbers, I expected there to be a significant inverse relationship between Air Yards and YAC, where short passers would produce the most YAC and deep passers the fewest. It turns out the effect is real, but fairly muted. At the season level, there was a -0.26 correlation between Air/C and YAC/C, with an r^2 of just 0.07. In other words, only 7% of the variance in YAC can be explained by the variance in Air Yards. To test this further, I checked the consistency of mAir and mYAC. Starting in 2007, I measured the year-to-year correlations for both metrics, including all QB’s who threw at least 100 passes in year n and year n+1. Here are the correlations:

Years	mAir	mYAC	n
12_13	-0.01	0.08	32
11_12	0.4	0.14	28
10_11	0.47	0.11	31
09_10	0.46	0.49	34
08_09	0.52	0.07	30
07_08	0.29	-0.21	27
Avg	0.35	0.11	30.3

It appears that Air Yards are roughly three times as sticky as YAC from season to season. From this, we can infer that Air Yards are primarily the domain of the QB, while YAC is mostly a product of coaching, receiver skill, the defense’s ability to tackle, and a heavy dose of plain old luck. The oft-proposed theory that a QB can increase his receivers’ YAC by hitting him perfectly in stride appears to be minimal. However, I’m willing to believe that there are rare exceptions, such as Joe Montana and Steve Young, whose Y/A often greatly exceeded that of other QB’s despite playing in short passing offenses. My data set includes most of Young’s 49ers career (1992-1998), and he was well above average in both mAir and mYAC (+1221 and +1620, respectively).

Coming soon: In my final post in this series, I will be tying together mAir and mYAC, looking at the career totals for every QB since 1992.

References:

Sporting Charts (Air Yards data)

Pro Football Reference (standard passing stats)

Tagged as: Adam Steele, Air Yards, Guest Posts, YAC

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