The Atlanta Falcons had the NFL’s most explosive offense this season, racking up yards and points with efficiency and balance. As a result, the Falcons are the NFC’s No. 2 seed in the playoffs, quarterback Matt Ryan is a leading MVP candidate and offensive coordinator Kyle Shanahan is reportedly interviewing for four different head-coach openings.The Falcons led the NFL in many offensive metrics this season, finishing No. 1 in points per game (33.8), yards per play (6.7), per-drive scoring rate (52.6 percent) and Football Outsiders’ offensive DVOA (Defense-adjusted Value Over Average).But Ryan, Shanahan, star wideout Julio Jones and the Falcons’ dynamic tailback duo of Tevin Coleman and Devonta Freeman were all in Atlanta last season, and the Falcons finished below or around the league average in all of those categories.So what has transformed an underperforming offense into the most effective unit in the NFL?Nearly every element that has made the 2016 Falcons offense special was on display in Week 12, when they welcomed a hungry, talented Arizona Cardinals defense. Despite their struggles with consistency, the Cardinals ended up finishing first in sack rate (8.1 percent), second in yards-per-play allowed (4.8), ninth in per-drive scoring rate (32.1 percent) and 10th in per-drive turnover rate (13.0 percent).The Cardinals received the opening kickoff and then drove for a touchdown, putting Ryan and company in a 7-0 hole. How the Falcons offense answered is a microcosm of how it’s dismantled NFL defenses all season long.Anchoring the run gamePerhaps the best free-agent acquisition of the offseason, center Alex Mack — the second-highest rated center in the league, according to Pro Football Focus — has transformed the Falcons’ line, providing a vital boost to the team’s pass protection and run-blocking. And his leadership on the team has set the tone for the Falcons’ young offensive line, Falcons general manager Thomas Dimitroff told me during an August interview on SiriusXM’S “NFL Inside Read.”On Monday, Falcons head coach Dan Quinn called Mack a “real critical factor in what we do and how we play.” That was evident on the second play of the Falcons’ opening drive against the Cardinals in Week 12.On a zone run to the left, Mack (No. 51) engaged and overwhelmed Pro Bowl defensive end Calais Campbell (No. 93). Freeman (No. 24) cut behind Mack’s block and exploded through the opened seam:Video Playerhttps://fivethirtyeight.com/wp-content/uploads/2017/01/538_falcons_mack-1.mp400:0000:0000:12Use Up/Down Arrow keys to increase or decrease volume.Football Outsiders’ offensive line metrics rank the Falcons 10th in Adjusted Line Yards (4.09), up from 15th (3.82) last season. The balance provided by being able to run the ball is keeping the Atlanta offense on schedule and the chains moving; the Falcons’ run game was third in expected points added (+22.12) this season, up from 31st in 2015 (-62.96).Outstanding receiver playJulio Jones’s raw numbers this season were down from 2015, when he was a first-team All-Pro and led the league with 1,871 yards on 136 catches. But his efficiency is up significantly, and the Atlanta offense has been better for it. During the 2016 regular season, Ryan targeted Jones on 24.2 percent of his pass attempts, down from his force-fed 33.1 percent rate in 2015. The effectiveness of new receivers Mohamed Sanu and Taylor Gabriel, plus the continued impact of Freeman and Coleman out of the backfield, means that the entire Atlanta offense doesn’t have to run through Jones anymore. With Jones free to concentrate on beating defenses deep, his yards per catch exploded from a career-low 13.8 last season to 17.0. That’s Jones’s highest mark since his rookie season (17.8), when he was a high-powered complement to veteran No. 1 Roddy White.Ryan’s accuracy and ball placement haven’t been markedly better this season than in the past, as Sam Monson of Pro Football Focus wrote, but his receivers are getting open more often and catching the ball much more reliably.Gabriel (1st), Jones (2nd) and Sanu (34th) all rank among the top 35 receivers in DVOA, reflecting the per-play value each delivered on passes thrown their way. But Ryan’s collection of weapons is so robust that even down-roster players make big contributions. On the opening drive against Arizona in Week 12, rotational wideout Justin Hardy made a spectacular catch that turned an incomplete pass into a 27-yard gain:Video Playerhttps://fivethirtyeight.com/wp-content/uploads/2017/01/538_falcons_hardy.mp400:0000:0000:17Use Up/Down Arrow keys to increase or decrease volume.Dictating matchupsBut watch the Hardy catch again: The tight end goes in motion right, then turns around and sprints out to the left flat. The offensive line sells a zone run to the right, only for Ryan to sell a play fake and roll back to the left. Hardy’s two-move route takes him with the run action, then upfield, then back out to move with the quarterback.All-Pro Cardinals cornerback Patrick Peterson should have no problem covering a fourth-string wideout one-on-one, but his eyes are checking on the run action. By the time he gets his head around and watches Hardy make a second move, there’s too much separation for Peterson to recover. Ryan puts it high, and Hardy makes an outstanding catch.Throughout the drive, Shanahan uses motion, spread formations, bunch formations and varied personnel packages. Sanu lines up outside, inside — even as a Wildcat quarterback, fooling a linebacker with a read-option keeper:Video Playerhttps://fivethirtyeight.com/wp-content/uploads/2017/01/538_falcons_sanu_b.mp400:0000:0000:18Use Up/Down Arrow keys to increase or decrease volume.Any offensive coordinator can install a bunch of goofy looks and pre-snap window dressing. But Shanahan is dictating matchups and getting players open.Aggressive coachingThe 11-play touchdown drive (discounting a defensive penalty on the Cardinals’ 2-yard line) seems like a master class on how to execute a scripted game plan against a stout defense.But the Falcons’ offense did fail at one point in the drive. Peterson sniffed out a screen to Freeman on a 2nd-and-4 play from the Arizona 44, and on the next play, Coleman was stopped three yards short of the sticks.A 4th-and-3 in opponent territory? Other NFL head coaches might punt the ball away and surrender possession, but Quinn went for it. Shanahan dialed up a rub route, and Sanu made a drive-saving catch.The Wall Street Journal named Quinn the fourth-most-aggressive head coach of 2016, factoring in fourth-down decisions, play-calling and special-teams decisions. By pressing his talent and scheme advantage, Quinn is maximizing his chances of winning.It’s not just that Ryan has cut his interceptions down this season, from his career rate of 2.4 percent to 1.3 percent. It’s not just that the offensive line is playing much better, receiver depth is dramatically improved or that the coaches are getting optimal results from the available talent. It’s all of these factors coming together to challenge NFL defenses on every front — and make the Falcons look as ready as anybody to make a Super Bowl run.Check out our latest NFL predictions.