Do Hypothetical and Actual Willingness to Pay Differ in Choice Experiments? - Application to the Valuation of the Environment

In this paper we test the validity of choice experiments with donations for environmental projects. In particular, we test whether or not willingness to pay for projects differs between a hypothetical and an actual choice experiment. Our results do not indicate that choice experiments suffer from overstatement in hypothetical willingness to pay; and this contrasts the results found in external tests of validity in Contingent Valuation. In addition, internal tests of validity indicate transitive and stable preferences in both experiments.