It’s not surprising that neither network wants to experiment with a host who doesn’t fit the established conventions for the 11.30 p.m. timeslot. Programmers at both networks surely recall how audience ratings at NBC declined in 2010 when it briefly replaced Jay Leno with Conan O’Brien.
1 A portfolio is used to balance risks. A program with large variations in audience size has a large risk. If the programs has an unusually large audience, the risk is rewarded with increased advertising revenue. But if the program has an unusually small audience, ad revenues will also be small. Programmers could use programs that consistently attract larger audiences to balance the risk of adding programs that might result in smaller audiences. But the study found programmers are reluctant to include risky programs in their portfolios. Programmers create portfolios to minimize the variation in audience size, which minimizes any instability in their ability to generate ad revenues.