Ron Rivera is now 14-16-1 in games decided by a touchdown or less. That number used to be 2-14.— Darin Gantt (@daringantt) October 18, 2015
Some of that is likely simple chance, as there's very little evidence that anyone can consistently lose or win close games. This is a very positive stat for the Bucs, though. Lovie Smith lost a whopping nine games by a touchdown or less last year, winning exactly one. This year, he's won two and lost none. Had the Bucs been better at close games last season, they could have been a winning team. That seems absurd given the low level of play they put out there last season, but it's an indication of just how close the margins in the NFL are and how easy it is to fall to one side or the other.
In addition, Rivera has helped his chances by turning into Riverboat Ron and actually going for it with some frequency on fourth down, refusing to settle for field goals and short punts in promising positions. He didn't exactly turn into the gambler his nickname suggests, still settling into the NFL average basically every season, but he wasn't as ludicrously passive as he'd been before.
Obviously, simply playing better (especially on defense) helped as well.
Lovie Smith hasn't been particularly passive in these decisions, at least compared to NFL averages, but his playcalling has been particularly conservative this year (even if that was arguably the right decision in that specific case) and he was very passive last season. If he wants to take some lessons from his former defensive coordinator, Smith should consider loosening the reins on the offense a little bit. It certainly can't hurt.
Overall, more luck in close games and a bit more aggressiveness by Lovie Smith could see the Bucs ending the season with a winning record even if their play remains sub-par. That's the kind of league they're playing in.