不确定性影响下的平均支付意愿参数估计

条件估值法(CVM)是估算环境物品经济价值最主要的技术方法之一。由于条件估值法中的支付意愿依赖于受访者的看法,而不是他们真实的市场行为,因此存在着诸如调查者提供的背景信息不充分、问卷格式不同等一系列不确定性因素,这些都将直接影响到受访者的支付意愿。对支付卡式(PaymentCard)调查问卷进行了扩展,增设一道反映受访者对其投标数值的确定性程度问题,在此基础上建立了支付意愿的不确定性模型,并以评估宝天高速公路(牛背至天水段)沿线生态环境的总经济价值为例进行了实证分析。研究结果表明:运用不确定性模型计算出的平均支付意愿为32.12元,总经济价值为284～349万元;与不考虑不确定性因素计算出的平均支付意愿(62.17元)相比,二者相差1倍;而总经济价值相差近294～327万元。这表明,CVM中不确定性因素对平均支付意愿影响很大,如不考虑将导致计算结果不精确,甚至存在较大误差。

Parameter estimation of average willingness to pay under uncertainty effect

The contingent valuation method(CVM)is one of the most dominant techniques for estimating the economic value of environmental goods.The willingness to pay(WTP)of respondents depends on their opinions but not the true market behaviors,so there are many uncertainty factors such as insufficient available environment information and different questionnaire formats.These uncertainty factors immediately affect respondents' WTP.This paper is mainly concerned with contingent value estimation in the presence of response uncertainty.We expand the questionnaire regarding payment card type by adding a question reflecting the degree of certainty respondent's payment.Then we attempt to build the uncertainty model which is used to estimate the total economic value of protecting the ecological environment along the Baotian highway.The results indicate that using the uncertainty model the average willingness to pay is 32.12 RMB and the total economic value of ecological environment is 2842-3487 thousand RMB.There is a great contrast between 32.12 and 62.17 which is the average willingness to pay without considering uncertainty.Especially the difference of the total economic value arrives at 2939-3266 thousand RMB.This shows that uncertainty has a very large affect on the mean WTP.Not considering uncertainty will lead to imprecise results or a large error.