How TV Ratings Work
Audimeters, people meters, ratings and shares. Nielsen began measuring US TV audiences in 1950 with a device based on the radio Audimeter. How ratings and shares work and why they decide a show's fate.
A TV control room: Asterzenback, CC0
Who decides if a show lives or dies?
Every time you hear that a show was cancelled for low ratings, a measurement company is in the story. In the United States, the big name is Nielsen, a company Arthur C. Nielsen founded in Chicago in 1923. It started out doing market research on products, not television.
In 1936 Nielsen acquired the rights to the Audimeter, a device that attached to a radio and recorded when it was on and which station it was tuned to. That little box turned the company into the referee of broadcasting.
From radio to TV
In 1950 Nielsen launched its Television Index in the United States, using a device based on the Audimeter to record TV tuning. That same year it bought the rival C.E. Hooper ratings business. Paper diaries filled in the details about who was watching.
By 1985 Nielsen was metering TV viewing in more than 5,500 American homes. In 1987 it launched the People Meter, which let each person in a household log in, so national ratings could come with daily data on age and gender.
Rating versus share
Two numbers matter. A rating is the percentage of all TV households watching a program. A share is the percentage of households with the TV actually switched on that are watching it. Because not every set is on, the share is always the bigger number.
That is why the Dallas episode that revealed who shot J.R. is remembered for its 76 share: about three in four TV sets in use that night were tuned to it.
Why it still matters
Ratings set the price of advertising, so they decide which shows get renewed. Measurement now also tracks streaming, delayed viewing and many screens, but the basic question has not changed since the Audimeter: who is watching, and how many of them?
Ratings can also create their own drama. A show that wins a big share might still be cancelled if it attracts the wrong audience for its advertisers, while a small but loyal audience can save a series. Networks watch the numbers the morning after every premiere and finale, and the weekly ratings report has decided the fate of countless shows over the decades.
Facts on this page were checked against these sources.
- A TV control room: Asterzenback, CC0
Text written by Drama Momma.
