http://bigstory.ap.org/article/af674018db6841e797be22120f0ad6f9/shotgun-offense-went-sparse-every-down-staple-nfl

Notably, most of the league's very best offenses relied comparatively little on the shotgun this season. The five highest-gaining teams (Saints, Falcons, Redskins, Patriots, Cowboys) all ranked among the eight that used the shotgun least frequently.

Four of the five teams that used the shotgun most ranked among the 10 poorest-performing offenses. One example: The San Francisco 49ers were in the shotgun 77.6 percent of the time (add in the pistol, with a smaller gap between center and QB, plus a running back hidden in the backfield, and the figure tops 90 percent) and were 31st of 32 clubs in average yards.

Chip Kelly, who was fired after one year as the Niners' head coach, likes the pistol because "your quarterback now can be a factor in the run game."

At the other end of the spectrum: Under offensive coordinator Kyle Shanahan, Atlanta accumulated 415.8 yards per game, No. 2 in the NFL, while being in shotgun a league-low 37.5 percent of plays.

"Every time you're under center, you've got a lot more run options and a lot more play-action options and a lot more movement options off of your runs," Shanahan said. "Your play choices are endless. You can do everything. Once you get into the 'gun, certain things are like cut in half. Play-action is not as good because it happens quicker. You can't hold the ball out there for as long and stuff. It just eliminates being as balanced."

One of his mentors, recently retired Denver coach Gary Kubiak, ran the second-fewest shotgun plays this season (41.6 percent). And while Kubiak also said he likes the way the shotgun helps the run, he noted there's no set-in-stone formula for success.

"It all depends what you are, how you're built," Kubiak said. "How your quarterback plays back there."

According to the 2016 data, though, teams actually put up better running numbers in the shotgun (4.95 yards per carry) than out of it (3.82). And passing was more efficient out of snaps under center, with a 63.6 completion percentage and 7.99 yards per pass attempt vs. 62.8 percent and 6.93 yards from the shotgun.

The key, it turns out, might be moderation: With Tom Brady running the show for Belichick, the Patriots never started less than 43.4 percent, or more than 55.6 percent, of their plays from the shotgun in any season from 2011-15, reaching at least the AFC title game every time.