 A discrete choice experiment DCE is the best available method to investigate the relative importance of characteristics of multi-dimensional concepts e.g. quality of care, characteristics of fertility treatments and allows the calculation of respondents trade-offs between characteristics Ryan and Farrar, 2000; Bryan and Parry, 2001; Sculpher et al., 2004; Telser and Zweifel, 2007; Albada and Triemstra, 2009. In a DCE, respondents have to choose repeatedly between choice sets, each described by characteristics with varying levels. 