In 2012 LIVES and FORS designed an experiment to provide evidence about which survey designs work best in the Swiss context, to maximise the quality of future quantitative research. As well as, to find the best combination of modes regarding response rates, biases, sample, budget and timing. Survey-based data collection makes a fundamental contribution to social science research in Switzerland. Because different features of the design of a survey can have implications for the quality of the data collected, optimising the survey design is key to ensuring the accuracy of the conclusions drawn from analyses of the data, and hence for the validity of both theoretical and policy developments derived from these. Today it is especially difficult to reach the households without a registered landline and it is increasingly difficult to convince people to participate. A multi-modal approach in terms of information gathering is thus increasingly necessary. This allows on the one hand to reach people through some specific method and not another and on the other hand people might be convinced to participate by offering the mode that suits them best (for some telephone, for others face-to-face or other). In this experiment, single mode surveys (paper, CATI and web) and sequential mixed mode surveys (CATI plus paper, and web plus paper plus CATI/CAPI) are compared with respect to response rates and the representativeness of the responding sample. The questionnaire was designed by selecting questions from various previous LIVES surveys and surveys executed by FORS, especially the European Social Survey (ESS). The selected questions related to the well-being and unease theme, but are also questions that seems particularly sensible to different modes, as under-representativeness of certain groups, different responses in different mode, etc. The results lend support to the conclusion that mixing modes sequentially can help to increase response rates and improve sample representativeness, though differences were observed as a function of the availability of telephone numbers for sample members.