The Use of Follow-Up Questions to No Responses in Dichotomous Choice Contingent Valuation Surveys

The dichotomous choice contingent valuation survey format collects inexact information on willingness to pay (WTP), that is, whether WTP is greater or less than the bid price. Sometimes researchers make the precise conjecture that certain respondents have zero WTP using information from follow-up motive questions. But follow-up questions are designed to provide information on respondents’ motives, not refined information on the magnitude of WTP. Assuming that certain respondents have WTP = $0.00 is beyond the design of follow-up questions. The paper's results show that unless information from follow-up questions is utilized within the limitations of survey design, welfare and model parameter estimates are likely to have high standard errors leading to inappropriate policy prescriptions.