In Switzerland, instead of estimating radio use on the basis of reported behaviour, we measure it. The system does not depend on participants filling out diaries or remembering what stations they listened to and for how long. Thus, the system provides very accurate data. Moreover, other than being willing to wear the measuring device for a short period of time, no active participation is required of the panellists. It is a passive system.

The measuring devices - in the guise of ordinary wristwatches - are worn by pre-recruited panellists for 7 consecutive days. The panellists form a cross section of the Swiss population aged 15 and above. With just over 1,000 measuring devices in daily use, we can provide reliable figures on radio listening of the permanent resident population (15+) of Switzerland.