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Guest Post: Touchdown Pass Vultures

Adam Steele is back for another guest post. And, as always, we thank him for that. You can view all of Adam’s posts here.


 

During the 2014 season, Chase noted that the league-wide touchdown pass rate was the highest it had been since the NFL merger. The final few weeks of the season dragged down the average a little bit, but 2014 still checks in as the most touchdown pass friendly year in NFL history. In response, a few commenters cited the possibility that teams were tallying more TD passes by sacrificing TD runs, which is a logical conclusion considering the very low rate of rushing touchdowns in 2014 (teams averaged 0.74 per game, the lowest since 1999). Today, I’m going to look into this further and see if teams really are inflating their passing TD numbers at the expense of the run.

First, we have to establish a historical baseline, and I did this by looking at every NFL season since 1950.1 In that time frame, teams averaged 2.26 offensive touchdowns per game, with 1.35 of those coming via the pass and 0.91 via the run. Translated into a ratio, offensive touchdowns have historically been 59.6% passing and 40.4% rushing. That 59.6% is the key number here, as it will be the baseline ratio for expected passing touchdowns. Below is a chart containing relevant information for each year since 1950. The “PaTD %” column represents the percentage of offensive touchdowns in a given year that were scored via the pass, and the “Inflation” column compares that year’s passing TD ratio with the historical average of 59.6%.

YearPassTD/GRushTD/GOffTD/GPaTD %Inflation
20141.580.742.3268%14.1%
20131.570.82.3766.2%11.1%
19651.571.012.5760.9%2.2%
19631.540.972.5161.4%3%
19621.531.092.6258.5%-1.9%
19521.511.022.5359.7%0.2%
20121.480.782.2665.4%9.7%
20101.470.782.2565.3%9.6%
19581.471.222.6954.5%-8.5%
19541.471.062.5258.1%-2.5%
20111.460.782.2465.1%9.2%
19871.450.862.3162.9%5.5%
19611.451.052.558.2%-2.4%
19671.450.982.4259.7%0.1%
19691.440.882.3262.1%4.2%
20041.430.812.2463.8%7%
19641.420.992.4158.9%-1.2%
19601.421.032.4557.9%-2.9%
19501.411.332.7451.4%-13.7%
20071.410.752.1665.1%9.2%
19831.40.982.3758.9%-1.2%
19511.391.222.653.3%-10.5%
20091.390.842.2262.3%4.6%
19951.380.82.1863.3%6.2%
19841.370.922.2960%0.7%
19981.370.792.1663.5%6.5%
19681.370.92.2760.4%1.4%
19591.371.12.4755.3%-7.1%
20021.360.92.2560.1%0.9%
19801.350.962.3158.4%-1.9%
19991.340.732.0764.7%8.6%
19851.330.992.3257.4%-3.6%
19661.330.952.2958.3%-2.1%
19811.320.982.357.3%-3.9%
19531.311.172.4952.8%-11.4%
19861.310.92.259.4%-0.4%
19961.30.762.0663.2%6.1%
19941.30.762.0663.2%6%
19891.30.872.1760%0.7%
19971.290.82.0961.6%3.4%
19901.280.842.1360.4%1.4%
20011.280.742.0263.5%6.6%
20001.280.832.1160.6%1.7%
20031.280.832.1160.5%1.5%
19821.270.922.1958.1%-2.5%
20061.270.832.0960.4%1.4%
20081.260.932.1957.6%-3.4%
20051.260.842.159.9%0.5%
19551.251.152.452%-12.7%
19881.240.952.1956.7%-4.8%
19791.21.092.2952.5%-11.9%
19751.191.132.3251.2%-14.1%
19571.181.12.2851.7%-13.3%
19701.170.81.9859.3%-0.5%
19931.150.681.8363%5.7%
19921.150.741.960.8%2%
19911.140.81.9458.8%-1.3%
19561.131.242.3747.5%-20.3%
19721.1112.1152.6%-11.7%
19761.11.062.1651.1%-14.3%
19711.070.911.9853.9%-9.6%
19781.041.012.0650.8%-14.8%
19731.040.911.9553.4%-10.4%
19741.0312.0450.7%-14.8%
19770.990.91.8952.4%-12%

As you can see, 2014 really did feature highly inflated passing TD totals, with 68.0% of offensive touchdowns coming through the air. This trend began in 2010, stabilized for four years, then jumped again significantly last season. The most obvious explanation is that teams are now passing more in general, so it would follow that they would also pass more to score touchdowns. But that’s only part of the story, as the rate of passing touchdowns has far outstripped the rate of overall called passes.

The main culprit appears to be goal line play selection, which has heavily favored the pass in recent seasons. Interestingly, from 1997-2009, there was no trend whatsoever, with passing TD ratios jumping around randomly from season to season. From 1980-1994, passing TD ratios were slightly lower, yet still very random. Even during the dead ball era of the 1970s, when the rules made passing far more difficult than it is today, teams still scored more often with passes than they did with runs. In fact, the famous 1956 season was the only time in the last 65 years where teams scored more rushing touchdowns than passing touchdowns.

But here’s what fascinates me the most: Despite the huge increases in total yardage and passing efficiency in recent years, offensive touchdowns have increased very little. In 2014, teams scored only 0.06 more offensive touchdowns than the historical average. In fact, the top 15 seasons for offensive TD production all came before the merger! If the NFL had been playing a 16 game schedule in the ’50s and ’60s, TD pass totals would be very similar to what we see today, and rushing TD totals would be higher.

So how does all this affect touchdown records for various quarterbacks? Since the 16 game schedule began in 1978, there have been 51 teams who scored at least 50 offensive touchdowns in a given season. Of those 51 teams, 33 of them had passing TD ratios above the historical average of 59.6%. In this chart, I list the primary QB, although the numbers represent team totals. The “Adjusted Pass TD” column is calculated by multiplying offensive touchdowns by .596, calculating how many TD passes would have been thrown by sticking with the historical average ratio. The “Change” column represents the difference in adjusted TD passes compared to actual TD passes, basically measuring how many TD pass were vultured from the run game.

YearTeamQBPassTDRushTDOffTDPaTD%Adj PaTDChangeInflation
2013BroncosManning55167177%42-1330%
2007PatriotsBrady50176775%40-1025.2%
1984DolphinsMarino49186773%40-922.7%
2011PackersRodgers51126381%38-1335.8%
2000RamsWarner37266359%381-1.4%
2011SaintsBrees46166274%37-924.5%
2004ColtsManning51106184%36-1540.3%
199849ersYoung41196068%36-514.7%
199449ersYoung37236062%36-13.5%
1981ChargersFouts34266057%362-4.9%
2012PatriotsBrady34255958%351-3.3%
1983RedskinsTheismann29305949%356-17.5%
1998VikingsCunningham41175871%35-618.6%
1998BroncosElway32265855%353-7.4%
2004ChiefsGreen27315847%358-21.9%
2011PatriotsBrady39185768%34-514.8%
2001RamsWarner37205765%34-38.9%
1985ChargersFouts37205765%34-38.9%
2010PatriotsBrady37195666%33-410.9%
1980CowboysWhite30265654%333-10.1%
2006ChargersRivers24325643%339-28.1%
2003ChiefsGreen24325643%339-28.1%
1986DolphinsMarino4695584%33-1340.4%
1999RamsWarner42135576%33-928.1%
2014BroncosManning40155573%33-722%
1991BillsKelly39165571%33-619%
2009SaintsBrees34215562%33-13.7%
199349ersYoung29265553%334-11.5%
1988BengalsEsiason28275551%335-14.6%
2008SaintsBrees34205463%32-25.7%
2005SeahawksHasselbeck25295446%327-22.3%
2012SaintsBrees43105381%32-1136.2%
2014CowboysRomo37165370%32-517.2%
2009VikingsFavre34195364%32-27.7%
198449ersMontana32215360%3201.3%
2004ChargersBrees29245355%323-8.2%
2002ChiefsGreen27265351%325-14.5%
2014PackersRodgers38145273%31-722.6%
1983CowboysWhite31215260%3100%
2014ColtsLuck4295182%30-1238.2%
2013EaglesFoles32195163%30-25.3%
2007ColtsManning32195163%30-25.3%
1985BengalsEsiason31205161%30-12%
1991RedskinsRypien30215159%300-1.3%
199249ersYoung29225157%301-4.6%
2000RaidersGannon28235155%302-7.9%
2011LionsStafford4195082%30-1137.6%
2007CowboysRomo36145072%30-620.8%
2003PackersFavre32185064%30-27.4%
1985DolphinsMarino31195062%30-14%
2009PackersRodgers30205060%3000.7%

I have plenty of thoughts about this chart, but I’m more interested to see what the readers think. Does this analysis change your opinion of any of these great QB seasons?

  1. AFL numbers were not included. []
  • Richie

    ” Does this analysis change your opinion of any of these great QB seasons?”

    Not really. I guess I’ve always made a bit of a mental adjustment, and just assumed that the top TD pass seasons got that way because teams were attempting to score via pass a little more often than usual.

    1999 Kurt Warner is the interesting one. It is one of the best TD Pass seasons, but was achieved without inflation.

    • Adam Steele

      Actually it was the 2000 season where the Rams dominated with a balanced Pass/Rush TD ratio. Warner and his backup Trent Green combined for 5492 yards, which would still be the record if achieved by one player. And despite being the most prolific passing team in history, the 2000 Rams also had 26 rushing TD’s.
      The 1999 version is remembered because they won the SB, but the 2000 and 2001 offenses were better.

      • Richie

        Oops. I misread the year in the chart.

      • Andrew Healy

        Neat stuff. It is interesting how the ’99 team was actually the least dominant version of those ’99-’01 GSOT Rams. They were only fourth in offensive DVOA! Played a historically weak schedule.

        • Adam Steele

          Yeah the ’99 team also had 11 return touchdowns which made their offense appear better than it was.

  • Alex

    I would go a bit further than Richie and say that I don’t see a compelling argument that I want to make any adjustment for play-calling except when comparing across eras. And even then, I would only want to adjust for the difference of the averages rather than the difference of individual players from the average. In order to consider the latter adjustment, some evidence is needed to show that deviation from average play selection is not the optimal choice. Otherwise, it can just as easily be argued that the inflation is actually a measure of how well that quarterback was playing.

    • Adam Steele

      Those are fair points. However, here’s how I look at it: a quarterback’s job is to drive his team down the field and into the endzone. It doesn’t matter how the final few yards are picked up. Therefore it’s entirely possible that a QB with 25 TD passes played just as well as a QB with 40, depending on goal line play selection, number of possessions, game situation, etc. Brian Burke and Aaron Schatz have both done studies showing the rushing is more effective than passing with one or two yards to go for a first down. I’m assuming that holds true for goal line plays as well. Of course that might change with a dominant passing game, but there’s no way to know for sure.

      When Mark Sanchez threw 26 TD passes in a single season, did that measure how well he played? Or how much confidence the Jets had in him? Maybe a little, but I’d argue it’s more a function of randomness. Play those games over and he could very well sacrifice 5-10 of those TD passes for TD runs.

      • Alex

        I completely agree, but you’re not making an adjustment for goal line play selection, number of possessions, or game situation. If you’re going to assume that any deviation away from the average is just a random occurrence, then I don’t see the point of the adjusted passing touchdowns. You can just as easily use total offensive touchdowns without scaling them by .596.

        What would make this interesting to me is if you tried to separate random deviations from deviations due to skill. For instance, since you argue that goal line play selection is the main culprit behind random fluctuations, perhaps you could only adjust touchdowns scored from less than 5 yards out. Or maybe you could adjust based on the percentage of the team’s offensive yards that the QB accounts for.

        • Richie

          Interesting. A comparison of TD’s by distance might shed some light. I assume this would be difficult to data mine.

          • Chase Stuart

            Assuming it wasn’t, how would you perform the study?

          • Adam Steele

            Data mining is indeed the problem. Finding the length of every TD pass for a given QB is easy, but finding the length of the rushing TD’s his teams scored while he was on the field is all but impossible without going through each boxscore by hand.

        • Adam Steele

          Frankly, the only reason I kept it this simple was in the interest of time. I used the .596 multiplyer to put offensive touchdowns on the same scale as TD passes, in the hopes of making the comparisons more intuitive, but you’re right that it isn’t really necessary. Also, play-by-play only goes back to 1999 so the historical perspective would not have been possible.

          I like your suggestion, and actually was contemplating something very similar (adjusting for goal-to-go situations). Long TD passes should almost always be credited to the QB, whereas a one yard TD has far more to do with playcalling. Those factors definitely need to be sorted out in order to have the most accurate results. Perhaps a future study is in order…

          Thanks for reading and commenting!