Schedule episodes of a show out of order
... More people sample a show when it's new, so networks try to run the best episodes first. ... Some episodes originally slated to air earlier in a season might have a problem and need to go back to the shop for more work ...
Move a show to different timeslots
... If it's a new show and it's clearly not working in its timeslot, it gets moved somewhere where it might work better ... If the show is doing badly but the network doesn't want to just take it off the air, it gets put somewhere out of the way so it doesn't hurt the shows around it. ... the old timeslot ... became problematic (like a ratings juggernaut aimed at the same viewers suddenly appears at the same time on a different network), or maybe a better [timeslot] became available ... so a new show gets the choice slot in an effort to give the new show its best shot at succeeding. Generally speaking audiences will follow good shows wherever they go. ... the network thinks it can do even better in the new slot ....
Don't leave a show on long enough to build viewers
... most series doing badly won't gain more viewers if they're kept running. In fact, they'll shed viewers. Every once in a LONG while a poorly performing show starts doing well. Those are the exceptions that prove the rule. ...
Take a show off the air quickly
Leaving poorly performing shows on the air hurts the shows around them and hurts the overall ratings for the network. ... replacing that show with something else that performs better will help fulfill ... commitment.
Put a show on hiatus
... A hiatus might happen around special events like holidays or the Olympics, so networks aren't airing new episodes of a show when no one's watching.
Schedule similar shows opposite one another
... Sometimes it's not ideal to leave a show where it is, but the network also can't rearrange its schedule to move the show. Sometimes shows that seem competitive really aren't.
Don't market a show well/at all
There is a finite amount of money and time available ... it might be the case that [the specific viewer wasn't one that was deliberately] targeted with ads because the network knew they'd find out about the show other ways.
Remake anything
... viewers love to watch remakes ...
Remake a recent remake
See above.
Listen to the Nielsen numbers/Not listen to the great DVR numbers
... Nielsen ratings ... are the best measurement tool that's proven workable at the scale needed ... Ratings are the currency of the TV business at the moment, and they're the only way to do business. If a TV network didn't want to use Nielsens it'd be like saying they want to start an ice cream shop but they'll only take gold bars as payment, not the standard cash or credit. ...
Don't understand a show
That thing you see in the show that you really love...the great characters, the charming premise, the new twist...someone somewhere at a network saw that before the show was a show, then made the show because of it. Which is why you're now seeing it.
Want a show to fail
If the network wanted a show to fail, they wouldn't put it on the air.
