La méthode d'évaluation contingente: De l'observation à la construction des valeurs de préservation

Abstract

Contingent valuation has been developped for assessing the costs and the benefits of a quantity or a quality change of non-marketed goods. Compared to other methods, contingent valuation has the particularity of asking directly agents about their willingness to pay for a desirable change or about their willingness to accept for an undesirable change. Since both the proposed change and the respondent's answer are hypothetical, a large discussion has been opened abouth the reliability of contingent valuation. We argue that the current debate has not yet addressed the fundamental questions, because current discussions rely on the presupposition that respondents hold "true values". The main question in this respect is one of designing a reliable methodology for observing those values. I shall argue however, that in most cases, environmental values are ill-defined, or even undefined. If this is the case, the data collected by any method, will be more often a construction rather than a real observation. The questions we ask are therefore: for what purpose is a method that constructs values usefull for ? How can such a construction be used for managing resources and the environment.