Heterogeneity of commercialization gains in the rural economy

Farmers in low‐income rural economies often fail to switch to cash crops from staple production despite the positive income effects of commercialization expected by policy makers. The literature suggests that market failures prevent households from cash crop adoption but remains inconclusive regarding farmers' motives and the effects of commercialization. This article contributes to the debate by offering an original approach to the analysis of commercialization outcomes and farmers' decisions. It consists of applying a model with essential heterogeneity and a semiparametric estimation technique to analyzing harvest value returns to cash cropping. Using Malawian data, we show considerable heterogeneity in harvest value returns to cash cropping both within and between groups of farmers choosing different crop portfolios. Importantly, the results imply rational choices based on comparative advantage considerations of farming households: farmers self‐select into the activity where they expect higher gains and adopt cash crops when facing weaker market barriers.     

农民国民待遇与制度伦理分析--兼论"三农"问题的解决对策

本文试图从制度伦理这一本原层面来探讨"三农"问题的解决途径。首先阐述了制度的本质,论证了制度绩效与制度伦理之间有着密切的正相关关系,并且认为自由与平等是制度伦理的两大基本原则,在此基础上指出,根据制度伦理精神,给予农民国民待遇是解决"三农"问题的必然选择,具体而言,就是废除二元户籍制度,给农民以真正自由的权利;改革不平衡的财税体制,使农民享受到均等的公共品供应和一视同仁的社会保障。     

Impact of Ghana's agricultural mechanization services center program

Use of mechanization in African agriculture has returned strongly to the development agenda, particularly following the recent high food prices crisis. Many developing country governments—including Ghana, the case study of this article—have resumed support for agricultural mechanization, typically in the form of subsidies for tractor purchase and establishment of private‐sector‐run agricultural mechanization service centers (AMSECs). The aim of this article is to assess the impact of Ghana's AMSEC program on various farm household outcomes, using data from surveys that were conducted with 270 farm households. A two‐stage propensity score matching and difference‐in‐difference estimation procedure is used to estimate the impacts of the program, employing different definitions of treatment, model specifications, and matching algorithms to assess sensitivity of the estimator to different assumptions. The results indicate that the AMSEC program has had a mixed impact on different outcome indicators. For example, whereas the program has contributed to improving availability of mechanization services, reducing drudgery, and raising yield, it has had no impact on the change in the prices paid by farmers for the services used and the change in the amount of area plowed. Implications of the results on labor‐mechanization substitution and for raising and sustaining productivity further are drawn.     

Analysis of treatment response data from eligibility designs

In this paper, we develop and compare two alternative approaches for calculating the effect of the actual intake when treatments are randomized, but compliance with the assignment in the treatment arm is less than perfect for reasons that are correlated with the outcome. The approaches are based on different identification assumptions about these unobserved confounders. In the first approach, which stems from [Sommer, A., Zeger, S., 1991. On estimating efficacy in clinical trials. Statistics in Medicine 10, 45–52], the unobserved confounders are modeled by a discrete indicator variable that represents subject-type, defined in terms of the potential intake in the face of each possible assignment. In the second approach, confounding is modeled without reference to subject-type in the spirit of the Roy model. Because the two models are non-nested, and model comparison and assessment of the approaches in a real data setting is one of our central goals, we formulate the discussion from a Bayesian perspective, comparing the two models in terms of marginal likelihoods and Bayes factors, and in terms of inferences about the treatment effects. The latter we calculate from a predictive perspective in a way that is different from that in the literature, where typically only a point summary of that effect is calculated. Our real data analysis focuses on the JOBS II eligibility trial that was implemented to test the effectiveness of a job search seminar in decreasing the negative mental health effects commonly associated with job loss. We provide a comparative analysis of the data from the two approaches with prior distributions that are both reasonable in the context of the data and comparable across the model specifications. We show that the approaches can lead to different evaluations of the treatment.     

"民工荒"的成因及对策分析

本文根据托达罗预期收益理论,对2004年以来我国部分地区出现的“民工荒”现象进行了分析,认为“民工荒”是农民工对预期收益与成本进行比较分析后做出的选择,并提出,要解决“民工荒”问题必须从提高农民工的工资待遇和改善农民工的社会福利入手。     

The treatment effect of borders on trade. The great war and the disintegration of Central Europe

This paper investigates the impact of changes in national border demarcation on economic integration. It treats the national breakups in Central Europe due to WWI as a natural experiment. The set-up allows to control for selection bias when estimating the impact of national borders on trade. A gravity model of trade is used to analyze goods-specific trade among Central European regions. The main results are, first, that systematic deviations of the observations under “border treatment” are found. Regions pairs that became separated by a new national border after WWI, tended to have below average levels of economic integration already before the war. A comparison of actual and biased result for goods-specific trade yields a difference of between 21 and 86% ad-valorem tariff equivalent, and might well be higher for certain goods. Second, the analysis indicates that cross-border integration was indeed lower after WWI but that this change was economically significant only for certain sectors. Third, in the interwar period, international trade was less diverted by borders first established after the war than by borders existing already before WWI. The results stress the importance of relative barriers to trade in attenuating the adverse effects of WWI on economic integration.

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Decentralization,market integration and efficiency-equity trade-offs: Evidence from Joint Forest Management in Ethiopian villages

Extant literature on Joint Forest Management (JFM) impact evaluation has concluded that it generally does not provide sufficient incentives to justify the costs that forest use restrictions impose on local people. However, there is a dearth of evidence concerning whether alternative JFM intervention with improved market linkages for non-timber forest products has similar implications. In this study, we evaluated the income and distributive effects of a JFM program in Ethiopia in which additional support was provided for improved market linkages for non-timber forest products (NTFPs). Exploiting exogenous variation in customary rights across eligible groups of communities that participate in JFM programs, as well as using heteroskedasticity-based instrumentations, we identified the income and distributive effects of the program. Our analysis shows that the program has raised the income of the households who chose to participate by approximately 400 Ethiopian Birr or 26% of per capita expenditure; that result was robust to various specifications. We also found that this effect is largely driven by marketing incentives to use non-timber forest products. However, we found that the program's benefit is biased toward the upper end of the income distribution, a result that points to the inequality-reinforcing effects of the program.     

Programme Evaluation with Multiple Treatments

Abstract.  This paper reviews the main identification and estimation strategies for microeconometric policy evaluation. Particular emphasis is laid on evaluating policies consisting of multiple programmes, which is of high relevance in practice. For example, active labour market policies may consist of different training programmes, employment programmes and wage subsidies. Similarly, sickness rehabilitation policies often offer different vocational as well as non‐vocational rehabilitation measures. First, the main identification strategies (control‐for‐confounding‐variables, difference‐in‐difference, instrumental‐variable, and regression‐discontinuity identification) are discussed in the multiple‐programme setting. Thereafter, the different nonparametric matching and weighting estimators of the average treatment effects and their properties are examined.     

最惠国待遇原则的经济学分析及应用策略

最惠国待遇原则是整个关贸总协定的基础,它本质上意味着一成员平等地对待其他成员,在不同成员之间实施非歧视待遇。最惠国待遇原则对规范成员方之间的货物贸易,对推动国际贸易的扩大和发展起了重要作用。用博异论对其作经济学分析并结合我国当前实际指出如何利用其规则和例外。     

城乡统筹视角下的农村环境基础设施建设

环境基础设施主要包括供水、污水处理、垃圾处理等公共设施,是提升人居环境和生活质量的物质基础。本文从我国农村环境基础设施现状入手,分析存在的主要问题,介绍国外有关经验,并在统筹城乡发展的视角下,提出明确政府责任、建立城乡统一的公共财政投入制度、多元化的供给机制和模式、创新基层村镇管理与服务机制、选择适宜的垃圾及污水处理技术等对策和建议。