Correlated discrete and continuous outcomes with endogeneity and lagged effects: past season yield impact on improved corn seed adoption

Farmers in Sub-Saharan Africa have lower agricultural technology adoption rates compared to the rest of the world. It is believed that the past season yield affects a farmer''s capacity to take on the riskier improved seed variety; but this effect has not been studied. We quantify the effect of past season yield on improved corn seed use in future seasons while addressing the impact of the seed variety on yield. We develop a maximum likelihood method that addresses the fact that farmers self-select into a technology resulting in its effect on yield being endogenous. The method is unique since it models both lagged and endogenous effects in correlated discrete and continuous outcomes simultaneously. Due to the prescence of the lagged effect in a three year dataset, we also propose a solution to the initial conditions problem and demonstrate with simulations its effectiveness. We used survey longitudinal data collected from Kenyan corn farmers for three years. Our results show that higher past season yield increased the likelihood of adoption in future seasons. The simulation and empirical studies indicate that ignoring the self selection of improved seed use biases the results; we obtain a different sign in the covariance.     

Birnbaum–Saunders sample selection model

The sample selection bias problem occurs when the outcome of interest is only observed according to some selection rule, where there is a dependence structure between the outcome and the selection rule. In a pioneering work, J. Heckman proposed a sample selection model based on a bivariate normal distribution for dealing with this problem. Due to the non-robustness of the normal distribution, many alternatives have been introduced in the literature by assuming extensions of the normal distribution like the Student-t and skew-normal models. One common limitation of the existent sample selection models is that they require a transformation of the outcome of interest, which is common R+-valued, such as income and wage. With this, data are analyzed on a non-original scale which complicates the interpretation of the parameters. In this paper, we propose a sample selection model based on the bivariate Birnbaum–Saunders distribution, which has the same number of parameters that the classical Heckman model. Further, our associated outcome equation is R+-valued. We discuss estimation by maximum likelihood and present some Monte Carlo simulation studies. An empirical application to the ambulatory expenditures data from the 2001 Medical Expenditure Panel Survey is presented.     

广东金融发展的环境分析和战略选择

“十一五”时期广东金融发展的国际环境、国内环境、区域环境以及省内环境与过去相比均发生了较大变化。广东要实现由金融大省到金融强省的根本转变,必须实施金融创新与改革、区域金融合作、金融安全、金融人才和协调发展五大战略     

文化产业发展中的政府行为研究

实践证明,政府行为对文化产业具有重要推动力量。对于文化产业刚刚起步的中国来说,政府对文化产业的管理存在很多弊端,其中越位、缺位、错位并存。笔者认为,在中国的文化产业发展中,应该借鉴发达国家政府驱动行为的成功经验,确定合理的行为取向,扮演好四种角色:决策者、服务者、监督者、管理者。     

影响中国投资乘数效率发挥的因素分析

财政政策实施集中体现了政策是在政府操纵下的一种公共行为,能够直接和间接地改变人们的利益结构,引起社会利益结构的变迁和行为的转变,并影响其他经济主体行为的政策选择。而投资乘数的存在,是宏观财政政策选择的重要依据,也是财政政策发挥程度的一种检验。对影响中国投资乘数效率发挥的因素研究有利于提高我国财政政策效率。     

The impact of attitudes and behavioral costs on environmental behavior: A natural experiment on household waste recycling

Numerous studies have shown the importance of incentives as well as of attitudes in explaining pro-environmental behavior. Reported attitude effects, however, are generally rather small and exhibit considerable variation among studies. Different theoretical perspectives can account for this finding: whereas theories of rational action suggest additive effects of costs and attitudes, the low-cost hypothesis and dual-process theories imply interaction effects - in different directions, resulting from different mechanisms. The present study tries to overcome the shortcomings of past research by using advanced statistical methods to test competitive hypotheses in the context of post-consumer waste recycling. We utilize data from a natural experiment on recycling participation in Cologne/Germany (n = 1882) in which the incentive structure for recycling changed due to the conversion of the recycling scheme from a drop-off system to curbside collection. In order to avoid self-selection bias, we conducted pre- and post-treatment surveys and applied conditional fixed-effects regression models. We found that curbside collection had a strong impact on recycling participation and attitudes had a moderate effect. The interaction is negative but statistically insignificant. Our findings contradict the low-cost hypothesis and provide some evidence that environmental concerns moderate the effect of the recycling scheme. We cannot, however, reject the rational choice proposition of mere additive effects.     

城乡统筹发展视阈下的重庆市失地农民就业问题分析与路径选择

近年来,失地农民在重庆各地不断涌现。尤其是重庆市被确定为“统筹城乡综合改革配套试验区”之后．伴随着城市化进程的加快,失地农民这个社会群体迅速膨胀。由此衍生的就业问题困难重重。能否很好地解决这一难题,关系到社会稳定扣经济健康发展,也关系到城乡统筹改革战略的顺利实施。本文将基于重庆的基本市情。结合“统筹城乡综合改革配套试验区”建设这个重大的契机,以开放的眼光探讨其解决路径和措施。     

边疆少数民族地区大学生择业心理比较研究——以新疆六所高校为例

运用自编问卷对新疆自治区六所高校的大学生择业心理状况进行了比较研究.结果表明,在自我评价维度上,民汉学生有显著差异,民族学生的自我评价高于汉族学生;专业因素是民汉学生择业时共同面临的首要障碍因素;民汉学生都有去基层工作的心理准备,但理想工作地区,民汉学生有显著差异;在首选单位上,民族学生更为保守,倾向于选择政府和事业单位;在收入期望上民汉学生都表现为过高期望.     

A model selection criterion based on the BHHJ measure of divergence

The aim of this work is the discussion and investigation of measures of divergence and model selection criteria. A recently introduced measure of divergence, the so-called BHHJ measure (Basu, A., Harris, I.R., Hjort, N.L., Jones, M.C., 1998. Robust and efficient estimation by minimising a density power divergence. Biometrika 85, 549–559) is investigated and a new model selection criterion the divergence information criterion (DIC) based on this measure is proposed. Simulations are performed to check the appropriateness of the proposed criterion.     

On parameter estimation for locally stationary long-memory processes

We consider parameter estimation for time-dependent locally stationary long-memory processes. The asymptotic distribution of an estimator based on the local infinite autoregressive representation is derived, and asymptotic formulas for the mean squared error of the estimator, and the asymptotically optimal bandwidth are obtained. In spite of long memory, the optimal bandwidth turns out to be of the order n^-1/5$n^{-1/5}$ and inversely proportional to the square of the second derivative of d. In this sense, local estimation of d is comparable to regression smoothing with iid residuals.