Origins

  In 1929 Claude Robinson, a student at Columbia University, applied to patent a device to "provide for scientifically measuring the broadcast listener response by making a comparative record of ... receiving sets ... tuned over a selected period of time." Robinson later sold his device for a few hundred dollars to the Radio Corporation of America, owner of NBC, but nothing more came of it at that time.

     Many realized that the least intrusive and most accurate way to keep track of listeners' radio tuning would be to attach some kind of mechanical recorder to the set. In 1935 Frank Stanton, a social psychology student at Ohio State University, as part of his Ph.D. dissertation built and tested 10 devices to "record [radio] set operations for as long as 6 weeks." (Stanton was later research director and eventually president of the Columbia Broadcasting System.)

     Others experimented with similar devices. Robert Elder of Massachusetts Institute of Technology and Louis Woodruff field-tested their device in late 1935 by measuring the audiences tuning in to Boston stations. But it was Arthur C. Nielsen, a consumer survey analyst with a degree in electrical engineering, whose wealth and fame would be made by the device. In early 1936, Nielsen heard a speech by Robert Elder, who called his device an "Audimeter." At the time the Nielsen Company, a consumer survey business, was primarily a collector of information on grocery and drug inventories.

     After receiving permission to use the Robinson-RCA device and some redesign of it, in 1938 the Nielsen Company began tests in Chicago and North Carolina. In 1942 the company launched the Nielsen Radio Index based on 800 homes equipped with the Audimeter, which recorded on a paper tape the stations a radio was tuned to. In the beginning, Nielsen technicians had to visit each of the 800 homes periodically to change the tape and to gather other information from each household based on an inventory of the family's food supply. The Audimeter was usually hidden from view in a nearby closet or some other out-of-the-way place. Respondents were usually given nominal compensation for their participation, and Nielsen usually shared repair costs on any radio in which the meter had been installed. Beginning in I 949, the receiver's tuning was recorded by a small light tracing on and off on 16 millimeter motion picture film that could be removed and mailed back to the Nielsen office in Chicago for examination and tabulation by workers using microfilm readers.

Audimeter Ratings

     The Nielsen Company soon supplanted the older and domi­nant Hooperatings, and Nielsen acquired the C.E. Hooper company in 1950. That year the Audimeter was used to record TV tuning for the Nielsen Television Index (NTI). The company also launched the Nielsen Station Index (NSI), which provided local ratings for both radio and television stations for specific market areas. In the same homes where Audimeters were in use, Nielsen obtained additional information on audience demographics by the use of diaries in which viewers were asked to record their listening and viewing of radio and television.

     Throughout most of the 1950s, as television's audience grew rapidly, the measurement of radio audiences by Audime­ters provided the most important information used by sponsors, advertising agencies, media buyers, and programmers. As network radio audiences declined and independent Top 40 stations rose, however, local ratings became more important. In 1941 a competitor called Pulse entered the ratings business and, with its ratings based on interviews, eventually eclipsed Nielsen.

     In the late 1950s and 1960s there was much criticism of broadcasting in general, resulting from scandals involving rigged quiz shows and disk jockeys being bribed in the "payola" scheme to play specific records, and there followed lengthy congressional investigations of ratings methodologies. As a response, Arthur Nielsen tried to develop a new radio index that would be above criticism but found it would be prohibitively expensive; advertisers and stations resisted higher costs. In 1963 the Nielsen Company ended local radio measurement and the next year withdrew from national radio ratings as well. The Arbitron rating company, founded in 1949 as the American Research Bureau (ARB), continued using meters for many years to supplement its diary method of radio ratings collection.

     Audimeters that merely indicate when a receiver is on, and to what station it is tuned, are now obsolete. Advertisers and station operators alike want to know who is listening-the listener's income, buying habits, location, level of education, etc. The Audimeter began to give way in television research (the new method was too costly to apply to radio) to the more expensive but also more useful "people meter," which can indicate who is listening by means of a remote control-type device on which each listener punches his or her key to show they are present. The people meter is connected by dedicated data lines to computers in Florida that provide overnight ratings.

     Since 1999 Nielsen, with Arbitron, the largest radio ratings firm, is testing a passive, personal meter, about the size of a pager, that listeners wear to record all electronic media use. As with the rest of radio, what began as a large device­ the "Audience meter"-has become much smaller and more portable.