Cam Newton took huge leap as a passer in 2015

Cam Newton was a career 58.8 percent passer through Week 9 of this season, but since then he's completed 65.9 percent of his throws, with 21 TD passes and only one interception. Jeremy Brevard/USA TODAY Sports

A quick glance at NFL statistics reveals that the league's three highest-scoring offenses all reached the championship round of the playoffs. That shouldn't be a surprise. Each of those teams has an MVP candidate playing quarterback and, last time I checked, the team that scores the most points wins the game.

But a closer examination of the data reveals an indisputable truth, one that was anything but evident earlier in the season. Carolina Panthers quarterback Cam Newton, long celebrated for his effectiveness as a runner, caught up to the NFL's elite passers in just about every measure imaginable. Newton finished the season not just playing as well as any quarterback in the league, but actually throwing it as well as the best too.

This might not sound revelatory, and perhaps you'll view it as another in a long line of condescending compliments toward a player who has struggled at times to win over impartial observers. It's not. Because as recently as midseason, most advanced metrics confirmed that Newton was an elite weapon as a runner but of average efficiency as a pure passer in terms of accuracy, touchdowns to interceptions and downfield effectiveness.

Newton shed that portrayal in an authoritative way during the second half of the season. The chart, researched by Jacob Nitzberg of ESPN Stats & Information, compares Newton's performance in the second half of the season relative to Arizona Cardinals quarterback Carson Palmer and the New England Patriots' Tom Brady. You'll see that Newton's Total QBR on pass plays was 91.2, nearly double his mark of 51.5 in Weeks 1-9 and higher than either Palmer or Brady over that span, and that no one in the league matched his ratio of 21 touchdowns to one interception after Week 9.

How did he do it? The numbers help tell the story. It might sound simple, but the most notable improvement Newton made was completing more of his passes.

Between the start of his career in 2011 and Week 9 of this season, Newton was a 58.8 percent passer, the fifth worst among qualified quarterbacks during that period. It was even worse during the first half of this season (53.7 percent), and that's a substantial 4½-year sample size. After Week 9 of this season, however, Newton completed 65.9 percent of his throws.

Newton's receivers deserve a portion of credit for that improvement. They lowered their drop percentage from 4.5 percent to 2.8 percent in the second half of the season. But the more notable surge came from Newton himself. He dropped his rate of off-target throws from 24.3 percent to 17.8 percent.

(ESPN Stats & Information judges each throw via video analysis on whether it was accurate enough to be in a receiver's catch radius. For context, 24.3 percent was third worst in the NFL over that span and 17.8 ranked No. 18.)

And it's not as if Newton's numbers improved because of some massive philosophical shift to easier passes. He maintained his downfield mentality throughout the season. In Weeks 1-9, Newton led the NFL with an average of 10.7 air yards -- the distance the ball traveled past the line of scrimmage -- per throw. After Week 9, that number dropped slightly to 9.83 air yards per attempt, a not-unpredictable figure given the impact of weather on passing and still high enough to rank No. 5 in the league.

So in sum, Newton spent the second half of the season throwing more touchdowns, fewer interceptions and completing passes at just as high an efficiency as the top passers in the league. Although he finished the season as the NFL's top rushing quarterback by yards (636), touchdowns (10) and first downs (57), by the end of the year he was producing four times as many points on passes (via 48.3 expected points added) than on runs (12.6).

(Here's an explanation for the expected points added metric, if you need it.)

It wasn't long ago that a serious public debate erupted when the Panthers signed Newton to a long-term contract that averaged $20.8 million per year. The Panthers had little choice on that number from a salary-cap perspective, but Newton had far from proved himself worthy of elite pay in the minds of many.

It's hard to make that argument anymore. Cam Newton has elevated himself into an elite quarterback in every way imaginable.