Does the solemn oath lower WTP responses in a discrete choice experiment application to solar energy?

Abstract

ABSTRACT A recently offered alternative to eliminating or mitigating hypothetical bias associated with stated preference surveys is the solemn oath script. While the efficacy of solemn oath script is still debatable, the objective of this analysis is to provide an initial field setting test of the solemn oath script to a particular discrete choice experiment survey application to solar energy. We conducted a discrete choice experiment survey with two treatment groups: with and without having respondents sign the solemn oath prior to taking the survey. Utilizing random parameter logit models in both preference-space and willingness to pay (WTP)-space, results provide no evidence that the solemn oath script lowers respondents’ WTP for the good in question. Either there is no hypothetical bias in this solar energy case study, which we are unable to test as there is no real expenditure at issue, or the solemn oath script may have limited application outside of the experimental lab and is not effective under every condition. Lastly, this calls for more research on the efficacy of a solemn oath script.