Nielsen: The company which measures television ratings through a large nationwide sampling of people of all different ages and backrounds.
Broadcast Network: A television network which is available free to everyone with a working TV. The five broadcast networks are ABC, CBS, The CW, FOX, and NBC.
Adult 18-49 Rating: This rating provides data of the percentage of adults between the ages of18 and 49 who are estimated to be watching a specific program based on the viewing habits of the Nielsen viewers. In the past this rating has been the one most correlated with which shows are ultimately renewed or cancelled, meaning we can make educated predictions by using these numbers.
This rating is the one primarily used in renewal/cancellation decisions for broadcast networks because it contains the age group of the targeting advertising audience. Many other demographics exist which can provide additional information that can uktimately make the decision of renewal or cancellation of a show that is considered a toss-up.
Share: The percentage of people in a specific age demographic who are watching a television show out of the number of people who currently have a TV on.
Total Viewers: This does not matter at all. Advertisers primarily care for the number of viewers within the age of 18 and 49 are watching the show, so if a show has a high number of total viewers but a low Adult 18-49 rating, it is still in danger of cancellation.
Syndication: After approximately 88 episodes, or four full seasons, a cable network may have the opportunity to air reruns of a broadcast show in syndication. Because so much money is made for shows through syndication, production companies will often lower the licensing fee on a show in its third season to ensure it receives a fourth. However, some shows in the past, such as Castle and Hawaii 5-0, have been lucky enough to acquire a syndication deal before their fourth seasons.
Sweeps Period: A sweeps period, taking place in February, May, August, and November, are used to determime future ad rates for a show. As such most shows air straight-through in these months as opposed to airing a rerun.