Working Knowledge; November 1996; Scientific American Magazine; by Aust; 1 Page(s)

In 1936 engineer Arthur C. Nielsen, Sr., attended a demonstration at the Massachusetts Institute of Technology of a mechanical device that could keep a record of the station to which a radio was tuned at any given moment. Nielsen bought the technology practically on the spot and six years later launched the Nielsen Radio Index, which analyzed the listening habits of 800 homes. Later, he adapted the same technology to the new medium of television, creating a ratings system that nearly all American broadcasters use today to help determine the popularity of their programs.

Over the years, Nielsen Media Research has used several methods to collect viewing information, including surveys and volunteer diaries. In 1986 the company supplanted these with an electronic device called a People Meter. The meter is now connected to televisions and telephone lines in about 5,000 households throughout the U.S.