Consistently strong play on both sides of the ball has helped the Cincinnati Bengals, Arizona Cardinals and Carolina Panthers combine for a 32-4 record through Week 13. The Seattle Seahawks and Kansas City Chiefs are taking a different path to late-season relevance, overcoming sluggish starts to climb sharply in their conference standings.
December's race to the 2015 NFL regular-season finish line will showcase teams in varying stages of performance. Some teams will sprint, gaining speed all the way. Others will limp. With that in mind, I've compiled the five offenses and five defenses that have shown the greatest statistical improvement so far this season.