Abstract Background The preferences of citizens are a basic element to incorporate into the decision-making process when planning health policies. Contingent valuation (CV) is a common method for calculating the value for citizens that new technologies, interventions, and the provision of services or policies have. However, choosing the correct CV tool may not be a neutral decision. This work aims to assess the substitution of a healthcare service by comparing valuation differences between the willingness to pay (WTP) for the maintenance of the service versus the willingness to accept compensation (WTA) for its substitution, both of which are related to subject characteristics, with a particular focus on trust in institutions and risk aversion. Methods A CV study was designed to study Dutch population preferences when physician assistants replace anaesthesiologists. Differences between the distributions of WTA and WTP were compared through full decomposition methods, and conditional quantile regression was ...