As FredH mentioned in his comment, in this particular case most of the gaps in NCIS correspond to political pre-emptions. However, even when there aren't these kinds of special things going on, most shows on the big networks have these kind of breaks. The reason is they are trying to make sure that they have shows for as many sweep periods as possible.
There can be many reasons for a mid-season finale:
The holidays. Most mid-season finales occur between Thanksgiving and January/February, sometimes as late as March. Lots of people get preoccupied with the holidays, especially holiday TV specials and programming, so stations put their key shows on hold so they don't lose ratings numbers. This is ...
Christmas features so heavily not because it was originally intended to be released in winter, but because of what the movie is about. It felt like a Christmas movie to the makers.
Jenna Anderson in her January 2019 article for ComicBook.com quotes
David F. Sandberg:
"Yeah, it's all about family and like Christmas time and this family holiday," ...
It seems to be mostly due to the convenience of the channel or network airing a series with a number of pre-recorded episodes or at least a batch of them. For example, when a network buys or syndicates a series that has, let's say, 10 episodes and start airing the episodes in december, if they air episodes 1 and 2 but the christmas episode of the series is ...
Many reasons including different time zones around the world, scheduling difficulties, promises to broadcast on one station first, to generate word-of-mouth interest.
**There are a few reasons for this.
Firstly, at this Metro article discusses, British shows are often scheduled at fairly late notice whilst American shows have their ...
The break coincides with the Winter Olympics, and allows them to air new episodes when they have a better chance of beating their competition for viewership, which (in turn) allows them to charge more for advertising.
Writing for season 2 started on January 2018. *
Filming for season 2 ended on November 2018. *
After that, they went into post-production and it was completed in April this year.
The trailer with the date announcement was released on April 26, 2019 — 33 years to the day after the day the Chernobyl disaster occurred.
You guys already figured out the ...
Obviously there's a lot of reasons, but two to consider are;
That some episodes will actually be cheaper to rerun due to the various cast/crew rerun terms - for instance most actors have at least two ways to get paid for a role; base pay plus rerun payments or base pay plus a buy-out fee that comes once no matter how often a show is reran.
I found a few things on the net about this.
Last of the Summer Wine is currently the most repeated show of since the beginning of 2013 in the UK (483 episodes shown).
The rest of the list is as follows:
My Family - 233 repeats
QI - One of only two current shows on list 179 times
Only Fools and Horses - Classic repeated 161 times
The Good Life - ...
I think the site tvseriesfinale.com will have what you want. In spite of its name, it is NOT solely about the finales of series, but deals in ratings and analysis of television in general. It also ranks shows and projects cancellation based on collected metrics. It presents ratings by network, including networks outside the "Big Three", and is kept updated ...