Assessing the Validity and Reliability of Contingent Values: A Comparison of On-Site Users, Off-Site Users, and Non-users

Imperfect information in contingent markets can affect the validity and reliability of contingent values (willingness to pay, WTP) for changes in natural resource allocations. Survey respondents can acquire information about the natural resource to be valued from behavior such as on-site use of the resource, off-site use of the resource, and/or from the survey itself. In this paper we compare the validity and reliability of WTP from respondents who obtained information in these different ways. Using theoretical validity tests based on relative prices as well as income we find that WTP is valid for respondents with information from on-site and/or off-site use. Willingness to pay is less valid for respondents who had no information about the natural resource before they participated in the survey. Using an alternative form reliability test, we find that WTP is, in the technical sense, reliable for all respondents and somewhat more reliable for on-site users.