“In the old days you knew by the third or fourth week if a show truly had traction,” said Mark Pedowitz, the president of the CW Television Network. “You’re now looking at seven or eight episodes before you get a determination. You’ll know more come some time by December and January.”

There are several reasons for this. Ratings are down across all of television, creating a level playing field where shows don’t have to stand out to survive. In between a few hits and a handful of shows on life support is a vast middle ground where even struggling programs can muddle on.

There are also more shows than ever — more than 400 will appear across broadcast television, cable and online services by year’s end, setting a record, and viewers are inundated with options. Executives want to give an audience time to find a show. And the networks also have access to a sea of data and statistics packed with delayed viewing numbers where, if one looks closely enough, it’s possible to find flickering signs of promise.

Glenn Geller, the new president of CBS Entertainment, said in an interview that “in the last couple of years, and certainly this year, you just kind of have to give it more time.”