A pré-história da medição electrónica, 40 anos antes

«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:

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;

In the same year, the radio ratings industry was in the dock, with a Congressional Hearing concluding that, based as they were on statistical estimates, all ratings were “inherently imperfect”.

Nielsen abandoned minute-by-minute measurement of radio, and the industry moved to a diary-based survey of radio audiences – an established methodology which was not without criticism. As one contemporary commentator noted in 1954: “…the placing of diaries can be a haphazard method scientifically, since many people refuse to accept them, which could throw an entire sample out of kilter. Also, there is a tendency to neglect filling out the diary until the last day of the week. Here, too, memory is unreliable and people will put down anything that comes into their heads—including, occasionally, shows which haven’t been on the air for years... As comedian Herb Shriner put it, “If you stop a woman leaving a supermarket and ask her to tell you everything she just bought, she won’t be able to. So how can she be expected to remember what she listened to a week ago?” Bill Davidson, “Who Knows Who’s on Top,” Collier’s, 29 October 1954.»

North, Nick e van Meurs, Lex,  «Radio Zapping», ESOMAR/ARF WAM, June 2004.

(obrigado Jorge)