Patients’ self-interest bias: Empirical evidence from a priority-setting experiment

This paper provides empirical evidence on the biasing effects of self-interest on patients’ stated preferences in a priority setting experiment. The analysis is based on a choice experiment to elicit preferences on the prioritization of patients on a waiting list for a non-urgent surgical intervention. We implement a procedure to test the existence of self-interest based on the similarity between respondents and the hypothetical scenarios they have to evaluate. Our findings indicate that when patients rank the hypothetical scenarios on the waiting list, they consider not only the explicit attributes described in each card but also the similarity of each scenario to their own. In particular, they assign a higher priority to those scenarios that better mimic their own states. Furthermore, we find that patients show a higher probability of providing “irrational” rankings than general public participants. The degree of similarity between the respondent patient and the dominated scenario partially explains this result.