This paper analyzes the possible advantages of the trichotomous choice elicitation question format in contingent valuation studies over the traditional dichotomous choice format. In the past, contingent valuation studies showed that mean stated willingness to pay (WTP) for a public project was...

Socially desirable responding (SDR) is an often-reported source of bias in survey interviews. It describes the tendency of a respondent to answer in a way that is socially desirable rather than to answer truthfully. This response bias also threatens the reliability and validity of survey-based...