Modelling winners and losers in contingent valuation of public goods: Appropriate welfare measures and econometric analysis

Contingent valuation is now the most widely used method for valuing non-marketed goods in cost-benefit analysis. Yet, despite the fact that many externalities manifest themselves as costs to some and benefits to others, most studies restrict willingness to pay to being non-negative. This can result in significant errors in policymaking. This paper examines the importance of this, explores appropriate welfare measures for assessing losses and gains, demonstrates how these can be elicited explicitly, highlights the sensitivity of the results of such studies to the econometric specification employed and suggests ways of dealing with it. Finally, the implications for policy are examined.