农机社会化服务采纳、禀赋差异与农村经济相对贫困缓解

进入以缓解相对贫困为重点的后扶贫时代，农村经济相对贫困问题仍不容忽视。农机社会化服务作为小农户与现代农业有机衔接的桥梁，对于推进乡村振兴战略和脱贫攻坚有序衔接具有重要作用。文章讨论的核心议题是农机社会化服务采纳如何缓解农村经济相对贫困，并尝试建立了“农机社会化服务采纳——禀赋差异缩小——农村经济相对贫困缓解”的理论分析框架。为此，文章首先对农机社会化服务采纳影响农村经济相对贫困的作用机制进行了理论分析，然后利用2750份河南省农户问卷调查数据，运用Logit模型，实证检验农机社会化服务采纳对农村经济相对贫困的影响，并通过替代核心自变量和变更样本的方法进行稳健性检验，运用PSM模型和IVProbit模型以及ERM模型进行内生性讨论，最后通过中介效应模型对其作用机制进行验证。结果表明，农机社会化服务采纳对农村经济相对贫困具有显著负向影响，缓解了农村经济相对贫困。考虑内生性后，结论仍具有稳健性。进一步的机制验证发现，农机社会化服务采纳通过缩小劳动力禀赋差异和技术禀赋差异，缓解农村经济相对贫困，劳动力禀赋差异缩小和技术禀赋差异缩小的中介效应占比分别为21.22%和7.36%。可见，应将完善农机社会化服务供需体系纳入农户相对贫困治理机制考虑范畴，引导农户从传统家庭化生产转向现代社会化生产，扩大农机社会化服务采纳范围；同时完善就业服务等相关配套体系以吸纳释放的弱劳动力，促进农户收入增长，缓解农村经济相对贫困。     

Some Cracks in the Empire of Chance (Flaws in the Foundations of Reliability)

Making quantified statements about the uncertainty associated with the lifelength of an item is one of the most fundamental tasks of reliability assessment. Most practitioners routinely do this using one of the several available statistical techniques. The purpose of this paper is two-fold. The first is to give the user an overview of the key tenets of two of the most commonly used parametric approaches. The second is to point out that these commonly used approaches involve strategies that are either ad hoc, or are in violation of some of the underlying tenets. A method that is devoid of logical flaws can be proposed, but this method is difficult to implement. The user must therefore resign to using that technique against which the fewest objections can be hurled.     

The Morishima gross elasticity of substitution

We show that the Hotelling–Lau elasticity of substitution, an extension of the Allen–Uzawa elasticity to allow for optimal output-quantity (or utility) responses to changes in factor prices, inherits all of the failings of the Allen–Uzawa elasticity identified by Blackorby and Russell [(1989) Am Econ Rev 79: 882–888]. An analogous extension of the Morishima elasticity of substitution to allow for output quantity changes preserves the salient properties of the original Hicksian notion of elasticity of substitution. We thank Paolo Bertoletti for drawing our attention to the issue addressed in this paper and for his comments on an earlier draft.     

中国A股市场规模溢价与价值溢价成因研究

金融理论界对规模溢价与价值溢价现象的困惑与争论由来已久，对上述现象的理论解释可以归纳为传统范式与行为范式。前者认为，溢价是对高风险的补偿，后者则认为，溢价源是对过度反应的纠正。为了弄清溢价形成的真正原因，本文对1993——2003年中国深沪A股进行了实证分析，研究发现：中国A股市场存在规模与价值溢价现象，但上述两种范式的解释均存在一定的局限性。本文借鉴展望理论的参照依赖原理，提出相对盈利的概念，并对溢价现象予以新的解释。     

Estimation in the generalized Poisson model via robust testing

An estimation method is presented which compromises robust efficiency with computational feasibility in the case of the generalized Poisson model. The formal setup is built on flexible nonparametric extensions of the underlying model. The estimation efficiency is expressed via minimax properties of tests resulting from expansions of estimators. The nonparametric neighborhoods related to the proposed score function are exemplified and a real data case is analysed. The resulting method balances several qualitative features of statistical inference: strong differentiability (asymptotic derivations are more accurate), efficiency and natural model extension (quality of formal basic assumptions).     

Robustness to the unavailability of data in block designs

We present general results for finding or boundingt _maxB , the maximum number of arbitrary whole blocks of observations which can be removed from a block design, and still leave all of the elementary treatment contrasts estimable. The block sizes may be larger than the number of treatments. The results are applied to BBDs, reinforced BIBDs and BBDs, BTIBDs, and a series of variance balanced incomplete block designs with two block sizes. Also given for most of these designs, are results fort _max, the maximum number of arbitrary, scattered observations that can become unavailable, and still leave all of the elementary treatment contrasts estimable.The work was undertaken while Dr. Whittinghill was visiting Ohio State University, and supported by a grant from the Natural Sciences Division, Colby College, Waterville, Maine.     

基于个税递延政策的企业年金保障水平研究

国家明确以税收优惠的形式鼓励和引导企业和个人参加企业年金计划,并于2014年实施了个税递延政策。基于指标模型构建和数据模拟,本文对我国企业年金在个税递延政策实施前后的保障水平进行了比较,通过参数敏感性分析考察了投资收益、工资增长、退休年龄和缴费比例等因素的影响。研究发现,实施个税递延政策后企业职工的养老保障水平在较大程度上低于政策实施前,但不同性别、不同收入水平和不同缴费比例的企业职工保障水平降低的程度有所差异。收入水平和缴费比例越高的男性职工,个税递延政策实施后保障水平降低的幅度越高,但对女性职工而言,这种影响要弱一些。进一步,可以通过增加投资收益、延迟退休年龄和提升缴费比例等方法来提高企业职工的养老保障水平,这与目前正在进行的一系列改革方向也一致。     

An empirical test of the Balassa-Samuelson hypothesis: Evidence from eight middle-income countries in Africa

The paper tests the validity of the Balassa-Samuelson hypothesis (BSH) using the within-effects and the dynamic panel generalised methods of moment (GMM) techniques for a panel of eight middle-income African countries over the period 1960–2009. We selected these countries because they exhibited a mixture of relative productivity growth and real exchange rate misalignment that fits the characterization of the BSH well. The results strongly support the BSH for this group of countries. The results are valid even after we controlled for potentially omitted variables and endogeneity. The implication is that as these countries become more productive, their currencies appreciate in real terms.     

Relative age effects in political selection

We exploit a regression discontinuity design to provide causal evidence of the relative age effect (RAE) on a long-run adult age outcome: Political selection. We find strong evidence of the RAE in politics in Finland. However, the effect is heterogeneous: We find that male candidates born early in the calendar year have a significantly higher probability of getting elected to the parliament but no similar RAE applies to female candidates nor to municipal elections. Moreover, this effect only takes place in the most competitive parliamentary districts and is present only for some parties. We also find that in all the groups where the RAE does not exist, early-born candidates are under-represented suggesting attrition of talent in the candidate placement. Overall, our results show that seemingly artificial cutoffs imposed by the government have persistent consequences even on the selection to the highest positions of power within a society.     

Knowledge sharing,knowledge leaking and relative innovation performance: An empirical study

External knowledge sharing and knowledge leakage often pose a strategic dilemma when firms conduct innovation activities. In this study, we focus on the positive and negative effects of this phenomenon. In particular, we empirically examine the effects of a firm׳s external knowledge sharing on its relative innovation performance under the contingencies of accidental and intentional leakage of business-critical knowledge. Results based on a survey of 150 Finnish technology-intensive firms show that external knowledge sharing has a positive effect on innovation performance, but high levels of accidental and intentional knowledge leakage by a firm׳s employees negatively moderate this relationship. These results contribute to the understanding of the potentially positive and negative issues related to external knowledge sharing and knowledge leakage, which have thus far remained empirically under-researched.