Willingness to pay and the choice of question format: experimental results

This study revisits the issue of hypothetical and actual willingness to pay. In two recent letters the validity of the contingent valuation method has been questioned. The studies include comparisons of hypothetical and actual economic commitments that were elicited through two different question formats. However, in order to attribute a difference in responses to a hypothetical bias, it must first be shown that the question formats generate equal responses under the same conditions. This letter not only contains the same comparison as the two recent letters, subsequent comparisons to investigate the question formats are also conducted. The rejection of equality between the two question formats raises questions concerning previous results.