Plausibility, the fourth objective, requires that a respondent find the scenario and
the payment vehicle believable. Lack of plausibility is a major source of error in
CV surveys because it keeps respondents from taking the choice situation seriously.
We took various steps to enhance plausibility, including the use ofWTP rather than
WTA elicitation questions.!! A referendum format asked respondents to make a
judgment as to whether they would vote for or against a program that, if adopted,
would cost their household a specified amount.