Some advances in optimal designs in contingent valuation studies

When an organisation such as a local or health authority or an environmental agency is considering making new or increased charges for a (new) amenity it might commission a survey in which a key question would be of the form:‘Are you Willing To Pay an amount X for the (new) amenity?’.This illustrates one type of contingent valuation (CV) study, namely, a dichotomous choice CV study with the figure X being a ‘Bid’ value. The paper will focus on double bounded CV's in which a second bid is offered.In particular we focus on optimal designs for the second bid of a double bounded study given the response at the first bid. These will be useful when there is a time gap between offering the two bids.