甘肃省耕地资源禀赋与贫困关系的量化研究

文章对甘肃省87个县以及其中的43个国家贫困县的耕地资源指标和贫困指标进行了相关分析,得出的结论是:甘肃省耕地资源禀赋与贫困之间没有相关性。因此要解决甘肃省的贫困问题,保证粮食安全战略,进而实现可持续发展的目标,必须提高土地质量,发展生态农业,增加单位面积的产出,并调整农业产业结构。片面扩大耕地面积不仅不能够提高粮食产量,反而会造成发展的不可持续性。     

退耕还林对延安地区农业经济的影响

对延安地区11个农业县退耕前后耕地/播种总面积、种植业结构、农业投入、粮食、油料产量与单产量以及农民年均纯收入的变化进行了研究,探讨了退耕还林对延安地区农业经济的影响及其作用机制。退耕还林优化了农村的种植业结构与产业结构,全面带动了农村经济的发展。但仍然存在着一些亟待解决的问题,并给农村经济带来了一定的负面影响。     

Provision Point Mechanisms and Field Validity Tests of Contingent Valuation

Past field validity tests of contingent valuation have relied on voluntary contribution mechanisms to elicit actual willingness to pay, and may overestimate hypothetical bias because of free riding in the actual contributions. This paper argues that provision point mechanisms are a preferred alternative for field validity tests of contingent valuation because they increase the proportion of demand revealed in cases in which public goods can be provided in a step function. The results of a contingent valuation validity study of participation in a green electricity pricing program that uses a provision point mechanism are reported, and hypothetical open-ended and dichotomous choice responses are compared to actual participation. Calibration of hypothetical responses is also explored.     

Willingness to Pay to Reduce Mortality Risks: Evidence from a Three-Country Contingent Valuation Study

Valuing a change in the risk of death is a key input into the calculation of the benefits of environmental policies that save lives. Typically such risks are monetized using the Value of a Statistical Life (VSL). Since the majority of the lives saved by environmental policies are those of older persons, there has been much recent debate about whether the VSL should be lower for the elderly to reflect their fewer remaining life years. We conducted a contingent valuation survey in the UK, Italy and France designed to answer this question. The survey was administered in these three countries following a standardized protocol. Our results suggest that the VSL is €1.022 million or €2.264 million, depending on whether we use median or mean WTP. The VSL is not significantly lower for older persons, but is higher for persons who have been admitted to a hospital or emergency room for cardiovascular and respiratory problems. Income is positively and significantly associated with WTP. The income elasticities of the WTP increase gradually with income levels and are between 0.15 and 0.5 for current income levels in EU countries. We use the responses to the WTP questions to estimate the value of an extension in remaining life expectancy. The value of a loss of one year’s life expectancy is €54,000 or €163,000.     

The Effect of Protest Votes on the Estimates of WTP for Use Values of Recreational Sites

Contingent valuation studies are often characterized by a considerable number of protest responses, which may cause selectivity bias on the final estimates for WTP. Sample selection models can detect and – if necessary – correct selectivity bias. In economic applications where the relevant dependent variable is continuous, sample selection models are generally estimated using Heckman's 2-step method rather than the FIML estimator. Either method has its own drawback: computational complexity for the FIML method, susceptibility to collinearity problems for the 2-step method. Using data on valuation of forest resources for recreational use, we analyse the performance of the two estimators. In this application, given the presence of some collinearity, the FIML is preferred to the 2-step method. A procedure is outlined to deal with selectivity problems in similar settings.     

黑龙江省典型城市合理用地规模确定的实证研究——以大庆市为例

以黑龙江省典型的资源型城市——大庆市建成区为研究对象,用1990—2004年的数据建立经济数学模型。利用Excel软件分析了城市用地规模与经济发展水平之间的关系,表明两者呈相互关联的非线性变化规律。假定在同一技术条件下,采取成本—效益模型计算出确保城市经济效益最优时的土地面积即为合理用地规模,通过计算城市空间扩展度,得出现有城市用地规模大于合理用地规模的结论,在今后的经济发展中应考虑适当地控制城市用地规模。     

Researching Preferences,Valuation and Hypothetical Bias

A number of recent papers in environmental economics have focused on the process of researching preferences – agents are uncertain about preferences but with effort may narrow their uncertainty. This issue has arisen in formulating bids in contingent valuation (CV) as well as the debate over the divergence between WTP and WTA. In the context of CV, it has been suggested that the hypothetical nature of the preference elicitation process biases responses. This paper provides both a theoretical model and experimental evidence to contribute to this debate. The model is a model of competitive bidding for a private good with two components that are particularly relevant to the debate. The first component is that bidders are unsure of their own value for the private good but may purchase information about their own value (researching preferences). The second component is that there is a probability that the auction is hypothetical – that the winning bidder will not get the private good and will not pay the winning bid. The experiment tests this theoretical model of bidding equilibrium and analyzes the effects of variations in the parameters (hypotheticalness, information costs and number of agents) on the endogenous variables (such as the proportion of bidders who become informed and the winning bid). Experimental results suggest that an increase in the hypotheticalness of an auction tends to decrease the likelihood that bidders pay for information on their valuation with an ambiguous effect on the winning bid.      

Stated Preferences, Real Behaviour and Anchoring: Some Empirical Evidence

We compare different contingent valuation question formats with each other and with observed behaviour for a non-monetary estimation task, the expected number of kilometers travelled by automobile. Open-ended questions, open-ended follow-up questions, dichotomous choice (DC) questions, and double-bound DC questions are included. The single and double-bound DC questions result in an estimated mean about twice as high as the actual value and the open-ended mean. The DC question overestimation seems to be due to an anchoring effect leading to yea-saying behaviour. Our results about the difference between DC questions and open-ended questions is consistent with the pattern observed in contingent valuations studies of the willingness to pay. Our results indicates that DC questions seem to be associated with a general overestimation problem that is present even for simple non-monetary estimation tasks.     

杭嘉湖平原地区土地利用变化驱动机制分析

选择位于杭嘉湖平原地区社会经济快速发展的浙江省海盐县为研究区,利用遥感数据,对研究区土地利用类型的空间转移与格局变化进行分析的基础上,选取研究区土地利用变化的社会经济驱动因子,运用典型相关分析方法诊断各社会经济驱动因子对土地利用变化格局形成贡献作用的大小,同时运用典型相关系数和冗余度分析,检验了分析结果。研究结果表明,人口密度、单位面积工业总产值、单位面积农业总产值、城镇化水平、农民人均年纯收入等5个因子是影响研究区土地利用变化的主要社会经济驱动因子。     

农村居民点用地的调查与思考

通过对柯城区农居点的调查,找出其中存在的问题,并进行相应的分析,最后提出通过编制村镇建设规划,加强农居点用地动态管理,建立农村居民点用地整理资金保障机制,以及通过健全农居点用地法规等手段来解决农居点的散、小、多、脏、乱、差等现实问题。