http://www.nytimes.com/2016/03/06/arts/television/ncis-meat-and-potatoes-tv-but-still-popular.html

The JAG spinoff really didn’t get going until its third and fourth season, when CBS realized it was a massive hit overseas. It wasn't until NCIS hit syndication that it became a massive hit for American viewers. “In L.A., I’d say I was on NCIS, and people would say, ‘Is that a radio station?,’” Michael Weatherly recalls of the early days. PLUS: The 5 most compelling (http://www.nytimes.com/2016/03/05/arts/television/ncis-5-best-episodes.html) NCIS episodes, Weatherly talks (http://tvline.com/2016/01/05/michael-weatherly-leaving-ncis-season-13/) about his exit, and the 12 biggest and best moments (http://www.tvinsider.com/gallery/76572/biggest-and-best-ncis-moments/).

I'd say it probably has something to do with the following factors:

- Older viewers. It really seems like the kind of show that older people are going to get into and I'm sure they make up the bulk of the viewership. So the question, for me, is what percentage of the show's 15 million or so weekly viewers are in the 18-49 demo? And of those who are, why exactly do they like the show?

- It's appropriate for all audiences. A lot of people don't like the dark themes, sexual content, violence, etc that are found in a lot of today's cable shows, so I guess those people can appreciate NCIS' sanitized, family-friendly nature.

- You can just drop into an episode and understand what's going on without having watched every episode leading up to it. So it's a show that can be watched casually, without being totally lost if you miss a week.

I'm in the 18-49 demo for another 2 years. I've watch since the beginning and I like it for all the reasons mentioned. It's hokey and not too taxing. Mark Harmon is the draw for me. If he left, I probably wouldn't watch as faithfully as I have been.