A Test of the Equality of Closed‐Ended and Open‐Ended Contingent Valuations

A test is developed to find whether open‐ended and closed‐ended contingent valuation mechanisms lead to significantly different results. The test is based on joint estimation of willingness to pay responses to open‐ and closed‐ended questions asked of the same sample of individuals. In a public good example, individuals do respond differently depending on question format. Possible explanations include different incentives for strategic behavior and respondents' lack of familiarity with the open‐ended question type. No differences in willingness to pay were found in a private good example.