By Max Mulitz
In this great post by Michael Lopez, we learn that NFL offenses are less effective on 3rd/4th & 1 from Shotgun than from Under Center.Below I did the same study Lopez did, except I broke the results out by runs and passes and I only used ArmChairAnalysis data from 2010-2015, as I feel the game has changed since 2000, especially with regards to how teams employ the shotgun formation. Results Below:
|Plays||Rush Conversion Rate||Pass Conversion Rate||Pass %|
First, notice rushing is much more effective than passing on 3rd/4th & short both from under center and shotgun. In spite of this, teams rush 82% of the time when under center but only 44% of the time from the gun. Breaking these tendencies out by individual teams/offensive coordinators would be useful for a team from an individual game planning perspective, but that’s a project for another day.
We also notice that rushing actually is more effective from the gun than under center and passing is slightly more effective from under center, a counterintuitive result. The advantage of rushing from Shotgun vs. rushing from Under Center was statistically significant at P=.05, while the advantage for passing under center vs. in the gun was not. The next step for this analysis would probably be to look at how Play Action effects the pass success rates both from the Gun and Under Center on 3rd/4th & Short.
One concern might be if teams can sustain success running from the shotgun on 3rd & short or if the success comes from the fact that teams rarely run. There were 9 teams that ran 50%+ of the time when in Shotgun, on average, these teams converted when running from the gun 76%, slightly above the sample average. The leader in gun % were Chip Kelly and Andy Reid’s Philadelphia Eagles, who were in gun 48% of the time on 3rd or 4th & short, ran on 78% of those plays and converted on an above average 77% of their plays when rushing. In total, 19 of 32 teams over the 5 year period were more successful running from the Shotgun than running from under center.
It seems that we have an example of Simpsons Paradox. Being in the Shotgun doesn’t seem to inherently lower a teams chance of converting on 3rd down and may even slightly help it when rushing, however because teams often line up in shotgun with the intention of passing on 3rd and 1 (a strategy with a lower payoff than rushing) Shotgun success rates fall behind Under Center rates.