Rationale, aims, and objectives: The literature suggests that discrete choice experiments (DCEs) are a preferable method for estimating willingness-to-pay (WTP) values, as they may avoid some biases often observed in contingent valuation surveys, such as protest and strategic behaviour. However, the choice studies have demonstrated that attribute non-attendance may be a serious issue that leads to biased WTP estimates.
Method:A DCE was used to estimate patients' WTP for dental care at the dental school clinic. The endogenous attribute attendance (EAA) model was used to estimate WTP for dental care attributes, while accounting for non-attendance to the cost attribute.Results: The EAA model revealed that almost every second respondent had ignored the cost attribute when making choices, indicating that patients were very sensitive to other characteristics of dental care. Dental care providers should pay particular attention to providing a detailed explanation of treatment to their patients, as this was the most valued attribute of dental care. The welfare estimates from the EAA model, which accounted for non-attendance to the cost attribute, were more than two times lower than welfare estimates from a traditional multinomial logit model and mixed logit model estimated in WTP space.
Conclusions:The findings raise concerns for derived WTP estimates in DCE studies that did not consider non-attendance to the cost attribute during the estimation process. Non-attendance to the cost attribute overestimates WTP values, even if being motivated by the true preferences of respondents.there are other formats of CV, such as the payment card format and dichotomous choice, they are all focused on the direct estimation of WTP for a hypothetical scenario. Instead of valuing the policy outputs as a whole, DCEs describe a good in terms of a number of characteristics or attributes that can take different values and are combined in an experimental design to describe different choice alternatives. Two or more alternatives are offered in each choice set, and respondents are asked to choose their preferred alternative. Respondents' choices imply implicit trade-offs between the levels of the attributes they would be willing to make, which could be used to estimate the weight or relative importance people assign to various service attributes. When the cost is included as an attribute, the marginal utility estimates from a DCE model can be converted into WTP estimates associated with the change in health care attribute(s). 4 Because of the indirect estimation of WTP, DCEs are often seen as a preferable elicitation method that may be less susceptible to adverse response behaviour often observed in CV studies, such as the protest and strategic behaviour. 2,3,5,6 However, recent DCE studies have shown that respondents often ignore one or more attributes when making choices, which may lead to biased WTP estimates. 7-9 Nevertheless, in most applications underlying preferences were estimated as if all attributes had been attended to. 8 This paper e...