O sistema Radiocontrol (GfK)

O grupo GfK tinha vários sistemas de medição electrónica, desde o sistema Eurisko, passando pelos relógio "radiocontrol" e "mediawatch".

Sobre o Radiocontrol, sabe-se que: «has been used in the UK for measurement of exposure to radio and TV by the Wireless Group since 2003. In the UK and across Europe, the technology has been used to measure in-home and out-of-home TV viewing of ‘hard to reach’ groups, and for cross media research on behalf of leading media agencies and international media owners.» De acordo com os seus responsáveis, «RADIOCONTROL is the electronic audience measurement system developed by Telecontrol, part of the GfK Group. RADIOCONTROL is a passive, electronic audience measurement device built into a wristwatch. Respondents are typically asked to wear the watch for a week during which time a built-in microphone records a short, four-second sequence of sound during each minute of the surveyed week. These sounds are stored not as sound files, but in a heavily compressed, digitised format, representing no more than audio ‘fingerprints’ of the original files. At the end of the surveyed week, the data from the watches are downloaded, and these listening records matched to a set of audio samples of every TV station and radio station monitored in the survey. If an audio fingerprint stored on the watch during a particular minute matches the sound sample of a particular station during the same minute, we may infer that this watch was exposed to this station at this time. By matching the sound samples recorded each minute by each watch to the stations’ broadcast output, it is possible to build up a minute-by-minute record of each respondent’s TV and radio listening. After extensive laboratory and field tests, the technology has been used in the national radio audience measurement system in Switzerland since 2000. In Great Britain, the system has been tested and trialled since 2001. In March 2003, The Wireless Group commissioned GfK to launch a continuous national survey of viewing and listening using RADIOCONTROL, from which the data for this analysis are drawn».