Wheat variety yield data: Do commercial and public performance tests provide the same information?

Wheat yields from reported performance test results are of economic importance to wheat producers, since their profits depend on selecting the optimal variety for their location. However, our data shows differences in absolute and relative wheat yields between commercial and public wheat breeding program's performance test data in Kansas. Newly available data are used to test if the difference in yields arose from potential selectivity bias, and to determine the contribution of private and public wheat breeding programs to varietal yield improvement during 2007–2012. Both Heckman selection models and multiple regression showed no statistical evidence of the potential presence of selectivity bias rather, managerial practices, agronomic conditions, field location, and inherent genetic traits of the seed variety were identify as the source of yield differences.     

How much do alternative cookstoves reduce biomass fuel use? Evidence from North India

Despite widespread global efforts to promote clean cookstoves to achieve improvements in air and forest quality, and to reduce global climate change, surprisingly little is known about the degree to which these actually reduce biomass fuel consumption in real-world settings. Using data from in-house weighing of fuel conducted in rural India, we examine the impact of cleaner cookstoves ⿿ most of which are LPG stoves ⿿ on three key outcomes related to solid fuel use. Our results suggest that using a clean cookstove is associated with daily reductions of about 4.5 kg of biomass fuel, 160 fewer minutes cooking on traditional stoves, and 105 fewer minutes collecting biomass fuels. These findings of substantial savings are robust to the use of estimators with varying levels of control for selection, and to alternative data obtained from household self-reports. Our results support the idea that efforts to promote clean stoves among poor rural households can reduce solid fuel use and cooking time, and that rebound effects toward greater amounts of cooking on multiple stoves are not sufficient to eliminate these gains. We also find, however, that households who have greater wealth, fewer members, are in less marginalized groups, and practice other health-averting behaviors, are more likely to use these cleaner stoves, which suggests that socio-economic status plays an important role in determining who benefits from such technologies. Future efforts to capture social benefits must therefore consider how to promote the use of alternative technologies by poor households, given that these households are least likely to own clean stoves.     

Short-term safety or long-term failure? Empirical evidence of the impact of securitization on bank risk

Based on a sample of U.S. commercial banks from 2002 to 2012, this paper shows that bank loan securitization has a significant and positive impact on both Z-scores and the likelihood of bank failure, indicating a short-term risk reduction and a long-term risk increase effect. We also find disparate impacts between mortgage and non-mortgage securitization. Loan sale activities are found to have a similar impact to securitization.     

Willingness to pay: Who are the cheap talkers?

The purpose of this paper is to determine who is willing to pay (WTP) for a greener event by applying a Contingent Valuation (CV) approach together with an experimental design. To identify the cheap talkers a survey was conducted at the Wacky Wine Festival in South Africa, were 474 respondents participated. Using a Heckman two-step approach, the results confirmed that the decision to contribute depends on behavioural and motivational factors, while the amount is income-dependent. The extent of cheap talking is significant, with a 50% deviation in stated and revealed behaviour. Besides cheap talkers, another category is identified, namely “ethicals”, who contribute their voucher to the tree planting project without indicating that they are willing to pay.     

基于拒绝推论的小企业信用评分模型研究

在小企业信用评分模型的构建中,因数据缺失和样本选择性偏差可能导致模型参数估计有偏,对模型的预测能力和应用会有很大影响。本文利用从万德数据库中筛选出的小企业信息资料,模拟银行信贷筛选,产生带有缺失数据的模拟信贷样本,利用Heckman二阶段模型预测新的信用评分模型,将其结果与忽略缺失数据的审查模型和基于完全信息的标准模型进行比较。结果显示,Heckman二阶段模型的表现优于直接忽略缺失样本数据的审查模型,更接近标准模型的结果。这表明拒绝推论能够有效解决信用评分建模中数据缺失导致的样本选择偏差,提高信用评分模型的有效性和预测能力。     

技术环境对菜农有机肥技术采纳行为的影响——以河南省设施菜农为例

目的 现阶段,我国化肥低效、过量施用的现象较为普遍,不仅增加农作物种植成本,还会对农业生态环境造成严重负面影响。因此,优化施肥结构,推广有机肥替代化肥对于加快实现农业绿色高质量发展具有重要意义。文章以设施蔬菜为例,从技术环境视角出发,以技术创新扩散理论为基础,分析了菜农有机肥技术采纳行为的影响因素。方法 基于河南省440份设施菜农的调研数据,利用Heckman两阶段模型分析了技术环境对菜农是否采纳有机肥技术和采纳程度的影响,并运用Logit模型和断尾回归模型进行稳健性检验。结果 研究结果表明,大多数设施菜农都采纳了有机肥技术,但采纳程度较低。有机肥使用成本、家庭务农数量、农产品畅销度、农产品价值认可度、参加技术培训和有机肥补贴政策对菜农是否采纳有机肥技术具有显著影响,而有机肥购买成本、有机肥使用成本、家庭务农数量、蔬菜种植规模、农产品价值认可度和有机肥补贴政策对菜农有机肥技术采纳程度具有显著影响。结论 政府部门可以采用多元化培训、跟踪式咨询服务、社群型学习小组等方式创新菜农有机肥技术培训模式,同时,通过加大有机肥补贴范围和力度、加快有机肥施用机械设备研发等措施降低菜农有机肥替代成本,从而提高菜农有机肥技术采纳行为。     

政府间转移支付、物流专业化与企业出口行为

文章以政府间转移支付、物流专业化影响企业出口行为的理论为基础,采用2000-2013年中国县级财政经济统计数据以及中国工业企业微观数据,运用Heckman两阶段法探究政府间转移支付、物流专业化与企业出口行为的总体关系。研究发现,政府间转移支付显著推动企业出口参与度的提高和出口规模的增长,物流专业化对上述企业出口行为均有显著的积极影响,政府间转移支付在物流专业化与企业出口行为的关系之间呈现显著的负向调节作用。在通过解决变量内生性问题、消除分配政策影响、考虑新冠肺炎疫情等外生冲击影响等一系列稳健性检验后,上述结论依然成立。进一步对政府间转移支付的异质性分析结果显示,一般性转移支付与物流专业化的交互项对企业出口参与度的回归结果变为正向显著。中介效应检验表明,政府间转移支付主要通过协调区域经济发展、基本公共服务均等化、改善财政收支结构促进企业自身出口参与和出口规模扩张;物流专业化主要通过物流规模扩张和物流效率提升促进企业出口二元边际增长。在新冠肺炎疫情长期持续和当前复杂艰难的国际贸易形势下,这一研究对我国继续优化政府间转移支付分配结构、强化物流专业化比较优势,进一步释放企业出口潜力,畅通国内国际经济双循环具有重要参考价值。     

Efficiency of the Banking Industry Structure in Korea*

This paper analyzes whether the efficiency of the Korean banking industry has improved since the bank restructuring in 1997, and whether a bank with high efficiency has a larger market share. This paper uses an efficient structure hypothesis model to examine the relationship between the banks' efficiencies and their profitability. The data envelopment analysis method is applied to measure the efficiency and profitability of the banking industry in order to minimize possible bias due to the inflow of public funds for the bank consolidation. The two‐step Heckman selection method is used to correct for survivorship bias in the model. The derived result indicates that banks with higher efficiencies tend to record higher profit. Moreover, higher pure technological efficiency and scale efficiency have a positive effect on a bank's market share and concentration.     

制度水平与双边股权资本流动——基于Heckman两阶段模型的分析

本文运用66个国家2001-2009年的双边股权资本流动数据,采用Heckman两阶段模型考察了制度水平对双边股权资本流动的影响。实证研究表明,母国和东道国的制度水平对股权资本投资决策和投资规模均具有显著的促进作用,但母国的制度水平起着决定性作用,一系列的稳健性检验也证实了制度水平对双边股权资本流动的作用是稳健的。此外,本文的研究还发现,传统的直接运用引力模型对双边资本流动的估计是有偏的,而Heckman两阶段估计是无偏估计。