Incentive incompatibility and starting-point bias in iterative valuation questions: Comment

In a recent study, Whitehead (2002) proposes incentive-incompatibility and starting-point-bias tests for iterative willingness-to-pay questions. We show that if restrictions assoctiated with the nature of starting-point bias are not imposed on the estimation, one obtains inconsistent estimates of the structural parameters and may draw inaccurate conclusions regarding the extent of incentive incompatibility and starting-point bias in contingent-valuation survey data.