Introduction Cost-effectiveness is an important criterion in the decision to cover interventions in health insurance packages. One of the outcome measures, the quality-adjusted life year, has been criticised on its assumptions and implications concerning life expectancy and quality of life. Several studies have been conducted that measured societal preferences concerning healthcare rationing decisions. These studies mainly focused on one attribute. To adjust quality-adjusted life year maximisation in accordance with societal preferences, the relative importance of attributes should be studied. The present study aims to measure the relative importance of age, gender, socioeconomic status, pre-intervention health state, treatment effect, chance of treatment success and number of people in need of the intervention. A secondary objective is to compare the validity of the willingness to pay method with the validity of a relatively new preference elicitation method, best–worst scaling. Methods and analysis A representative sample of 2000 Dutch citizens, over 18 years of age, are recruited to complete a web-based survey containing treatment scenarios. The scenarios present different levels of attributes. Respondents are asked to select one of the four scenarios that they prefer to be covered by the Dutch standard health insurance package and one that they prefer not to be covered. They are also asked to indicate how much they are willing to pay for each treatment scenario. At the end of the survey, respondents are asked to rate every attribute on a 1–10 scale. Two versions of the questionnaire are developed which differ on the framing, that is, treatments can be added to or removed from the insurance package. The data will be analysed by means of sequential conditional logit analysis (best–worst scaling) and analysis of variance (willingness to pay). Ethics and dissemination The protocol is reviewed and approved by the medical ethical committee of the University Medical Center Leiden.