Whilst contingent valuation is increasingly used in economics to value benefits, questions remain concerning its external validity i.e. do hypothetical responses match actual responses? We present results from the first within sample field test. Whilst Hypothetical No are always an Actual No, Hypothetical Yes exceed Actual Yes responses. A constant rate of response reversals across bids/prices could suggest theoretically consistent option value responses. Certainty calibrations (verbal and numerical response scales) minimize hypothetical-actual discrepancies offering a useful solution. Helping respondents resolve uncertainty may reduce the discrepancy between hypothetical and actual payments, and thus lead to more accurate policy recommendations.
Bibliographical noteWe thank respondents for taking part in the study and 2 anonymous reviewers for their helpful comments. Financial support from the University of Aberdeen and the Scottish Government Health and Social Care Directorates is acknowledged.
- contingent valuation
- external validity