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 (WTP) to being non-negative. This paper explores appropriate welfare measures for assessing losses and gains and demonstrates how these can be elicited explicitly. Statistical / econometric methods are presented for modelling such responses. Median WTP is estimated non-parametrically. Grouped regression / Tobit and grouped regression / hurdle models are used to identify the determinants of WTP and to estimate mean WTP.