For many years, television has had instruments of audiometric measurement at its disposal. These measurements are instantaneous, precise and specific (programme by programme). Fixed panels (same people interviewed on an eight week basis) are able to follow individual audience movements over long periods of time, and authorise specific analysis. Contrary to television, radio has inherent qualities which hamper audience measurements: numerous and mobile equipment, high number of broadcasting stations and away from home listening. Daily individual interviews (different sample each day) provide the market with statistics on the preceding day's audience volume per station. However, neither the listening patterns of the audience, nor the day to day variations in programmes heard are treated. Mediametrie's radio panel offers detailed information on these issues which fail to appear in the standard radio reference survey. Its duration over 23 days has enabled Euromedia to expand understanding of the audiences with information on the programmes. This is a new criterion in analysing the behaviour of radio listeners. The research and development undertaken by Euromedia provides an alternative and richer approach to quantifying radio listening. This is based on the knowledge of the programmes listened to. The degree of fidelity to one particular programme, the level of duplication and the changing of audiences between programmes have been analysed. A typology of audiences in relation to the types of programmes heard (news, music programmes, entertainment, etc.) allows us to define different patterns of listening behaviour. These results have enabled us to conclude that those who listen to the radio have a strategy of choosing preferred programmes. This strategy is related to their tastes, their interests, and more generally, the information they wish to acquire through the selected programmes.