Over the past two decades, economic theory has extended its field of application to non-market goods such as environmental resources and health. Although it is impossible to assign a price to these goods on the basis of market mechanisms alone, the fact that they have no price does not mean that they have no value. One technique in which economists have shown a marked interest is the contingent valuation method (CVM), which has mainly been used to assign a monetary value to environmental goods. It was first applied to natural resources used for recreational purposes. CVM has been applied to...