CBS’ NCIS has remained one of the best shows on television despite losing fan-favorites Mark Harmon, Michael Weatherly and Cote de Pablo. Here’s why.

The best part about NCIS has always been its impressively relatable characters. Unfortunately, not all of the characters have stuck around 20 seasons later. The series k***d off Agent Kate Todd at the end of Season 2, and after that, it seemed like someone was either being written out or k*****d off on a regular basis.

Yet NCIS has stayed popular amidst its cast turnover. Viewers worried about the series failing when Cote de Pablo’s Ziva David left, when Michael Weatherly’s Tony DiNozzo departed, and especially when Mark Harmon filmed his last episode as Leroy Jethro Gibbs. Every time the show has managed to rebound and has even outlasted its own spinoffs. There’s a clear secret to its success.
NCIS’ Excellent Characters Are Its Consistent Strength

After Kate was killed, Ziva came onto the series and immediately made an impact. It also didn’t take long before she was shipped with DiNizzo, despite Gibbs’ rules against dating coworkers. That continued until Ziva seemingly died in Season 11 and Tony left in Season 12. For a lot of series, that would’ve been the end. Tony had provided charm, comedic relief and pop-culture references from the very beginning. Then Ziva and Tony became a dynamic duo for nearly 10 seasons. Yet NCIS kept trucking along, adding Ellie Bishop and Nick Torres in their place. Both proved to be interesting characters in their own right, with Torres particularly shining in Season 20,

In “Big Rig,” Torres went undercover to find the missing Agent Sawyer. It took some arguments and posturing, but eventually, the two were able to work together to solve the case. The episode kept fans on the edges of their seats and it was a perfect example of how NCIS keeps adapting its stories to suit its new characters. Torres is known for his undercover work, while new team leader Alden Parker has provided stability in the wake of Gibbs’ departure. However, NCIS’ characters aren’t the only reason it’s survived so long.
NCIS’ Popularity Continues Because of Its Procedural Format

From classic series like Dragnet and Adam-12 to today’s Chicago P.D. and NCIS, watching crime fighters has enthralled viewers for a long time. NCIS is a particularly great iteration of the crime procedural and has found success because of that format. NCIS star Rocky Carroll told CBR why procedurals like NCIS are such good television. “As convoluted and as complicated as law and legal matters are in the world,” he explained, “there’s something very reassuring about turning on your TV and knowing that in the end, the good guys are going to win and the bad guys are going to get their just desserts.”

Carroll’s comments are spot on. If NCIS may seem simple or predictable some weeks, that’s the point. The procedural format gives viewers an idealized version of the world. Almost everything goes according to plan, the good guys win and the bad guys inevitably fail. It doesn’t matter whether the hero is Gibbs or Parker, DiNozzo or Torres, Ziva or Bishop, or now Jessica Knight, NCIS will attract viewers who want to see that kind of story. The show has a committed fan base and as long as it keeps delivering stories with interesting characters that fit the procedural format, it will outlast anyone’s departure.