Ex post mitigation of hypothetical bias using follow up certainty questions typically takes one of two forms: (1) two options, "definitely sure" and "probably sure", or (2) a 10-point scale with 10 very certain. While both have been successful in eliminating hypothetical bias from estimates of...

Use of the contingent valuation method is controversial among economists because it is based on hypothetical rather than real choices. Previous experiments have suggested that the commonly used dichotomous choice contingent valuation method leads to hypothetical bias, i.e., overestimates the...