The Ratings Secret: How One Decimal Point Can Decide Television’s Fate

Television ratings look like simple percentages, but they have helped determine what broadcasters make, what advertisers buy and what society understands as popular. For decades, the number served as a measure of what large groups of people were watching before search rankings and social media trends took over that role.

The highest rating in television history came during the Apollo 11 moon landing on July 20, 1969. The broadcast reached a 94% rating in the United States, while more than 600 million people around the world reportedly watched. In scripted television, the finale of the U.S. sitcom “M.A.S.H.” drew 105.9 million viewers in 1983. In South Korea, the combined rating across the country’s three major broadcasters reached 79.2% for the 1998 World Cup match between South Korea and Mexico. The final episode of the 1996 weekend drama “First Love” reached 65.8%, while “Sandglass” recorded a peak momentary rating of 75.4%.

Ratings began not with television but with radio. In the 1930s, a market research company bought a patent for a device developed in a U.S. university laboratory. The audiometer automatically recorded whether a receiver was switched on and which channel it used. Researchers deployed it in radio audience surveys in the 1940s and adapted it for television in 1950. The term “prime time,” referring to the hours when the largest audiences gathered, also emerged from this period of measurement.

Once ratings became an advertising scorecard, broadcasters began chasing them aggressively. In 1980, the drama series “Dallas” ended a season with its central character shot, then kept viewers waiting eight months to learn who was responsible. The reveal attracted 83 million viewers and a 76% household share. The cliffhanger became a powerful programming device.

The arrival of people meters in the late 1980s changed the question from how many households watched to which people watched, including their ages. That shift helped broadcasters target younger consumers preferred by advertisers. CBS canceled highly rated rural sitcoms such as “The Beverly Hillbillies” and “Green Acres” because their audiences were older and more rural, a decision later dubbed the “rural purge.” The article argues that a single change in measurement helped reshape American television and the wider content industry.