To clarify, I will define a niche comedy as a comedy which appeals to a very small but loyal fanbase, and is designed to be that way. For example, shows such as 30 Rock and Park & Recreation seemingly had the purpose of appealing to a very specific audience, whereas a show like Modern Family has an easier time at reaching a broader population.
Now this in particular is kind of bold, as in recent years, there really haven't been too many niche comedies air on Fridays. However, I still believe that it is idea worth exploring. Advertisers obviously want to receive full benefits for the amount of money they invest to place a 30-second ad during a show, and while some advertisements may be geared more specifically toward that niche comedy audience, I'm very willing to bet that they would want a broader show to air on a Sunday-Thursday night rather than on the lower-viewed Friday.
Let's make an example. You, the reader, also happen to be an executive at Ford, and want to advertise the newest Fusion car via a 30-second ad. Since you work for one of the biggest car companies in the country, you have plenty of money to invest in an ad. Since a Ford car is more likely to reach a broad audience, and broader shows have a higher chance of receiving higher ratings.
So, back to your ad: you place it during a broad new show that has potential to reach a large audience--except for the fact that it airs on Friday and is consistently fractional. Meanwhile, you have a niche comedy airing on a Sunday-Thursday night, which is disappointing in the ratings for those days, but has a larger chance of maintaining its loyal audience on a move to Friday. Moreover, that broad show could easily grow its ratings if time slots were swapped. It's a win-win situation for both the network and the advertiser.
Now I'm not trying to suggest that all of a sudden we move Bob's Burgers, The Last Man on Earth, and New Girl (when it premieres, at least) to Fridays--that would go against the Rule of Stability.
What I am trying to suggest is that networks may want to try to premiere newer shows on the night, or perhaps move an existing, but relatively new, show that is underperforming on a weeknight in the educated hopes that it will keep more of its audience percentage-wise than many other shows on a Friday move. That latter example at its best would be a prime example of the Rule of Reliability. Now we just need to find a show that's compatible with it and we're all set!
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The first test to my hypothesis? Undateable Live!