Measuring the Worth of Natural Resource Facilities: Reply
回应Hanemann的评论，强调经济学家不能总是用普通需求曲线下的面积来近似福利变化，因为资源设施的提供或消除会导致价格大幅变动，且需要知道需求函数形式才能计算补偿变差和等价变差。
We appreciate Michael Hanemann's clarifications of and comments on our paper (Bockstael and McConnell 1980) on using consumer's surplus to measure the worth of natural resource facilities. Hanemann's comments underscore our message: economists cannot always use Willig's (1976) results to assume that the area under an empirically estimated ordinary demand curve is a close approximation of the more appropriate measures of welfare changes. There are two difficulties. First, the provision or elimination of facilities induces large implicit price changes and potential large differences in welfare measures. Second, the use of the error bounds or the direct computation of equivalent and compensating variation requires a knowledge of the functional form of the demand curve. Measuring the economic value of providing and, especially, of eliminating natural resources is a difficult business. When the political process admits evidence from all affected parties, reaching a decision can be slow and often painful. Economists can help in the decisionmaking process by providing measures of welfare changes for benefit-cost analysis. There are times however when equivalent and compensating variation measures will be substantially different, and the economist's recommendation will