GfK Media Ltd, United Kingdom
Lex van Meurs
Intomart GfK, Netherlands
The minute-by-minute, mechanical measurement of radio audiences was first introduced in 1942. AC Nielsen's Audimeter registered each movement of the radio tuning dial with the scratch of a stylus on a roll of paper tape, storing the information in a cartridge, which at the end of each survey period was mailed back to the company for analysis. From 1950 until 1963, the Audimeter-based Nielsen Radio Index served the US radio industry as its official currency. Technological change and legislative action brought about its demise: (See Figure 1)
The sales of new, portable transistor radios starting in the late 1950s and the advent of stereo FM broadcasting in 1963, adding to the already growing number of channels that could be received, undermined the practicability of the system.