Contingent valuation (CV) measures what is called passive use value or existence value. The CV method has been used to measure the benefits of environmental policy actions. CV measures of economic value rely on choice. In CV studies, choices are posed to people in surveys; analysts then use the...

This paper reports an exercise in adversarial collaboration. An adversarial collaboration is an investigation carried out jointly by two individuals or research groups who, having proposed conflicting hypotheses, seek to resolve the issue in dispute. The experiment reported was designed to...