EXPERIMENTAL RESULTS ON EXPRESSED CERTAINTY AND HYPOTHETICAL BIAS IN CONTINGENT VALUATION

Use of the contingent valuation method is controversial among economis ts because it is based on hypothetical rather than real choices. Previ ous experiments have suggested that the commonly used dichotomous choi ce contingent valuation method leads to hypothetical bias, i.e., overe stimates the real willingness to pay. We carried out an experiment to compare the dichotomous choice contingent valuation method with real p urchase decisions for a consumer good. We confirm previous findings th at hypothetical yes responses overestimate real purchase decisions, bu t we cannot reject the null hypothesis that definitely sure yes respon ses correspond to real purchase decisions.