初始商业文化禀赋如何影响地区经济发展

基于中国省级层面的非平衡面板数据实证考察初始商业文化禀赋影响地区经济发展的内在机制及效应，结果表明，初始商业文化禀赋对地区经济发展具有正向的促进作用。为了避免内生性问题对计量结果的有偏性影响，使用1949年地区商业贷款占比和地区识字率变量作为初始商业文化禀赋的工具变量。 IV估计结果表明，初始商业文化禀赋与地区经济发展具有显著的正相关关系。     

Encouragement Designs: An Approach to Self-Selected Samples in an Experimental Design

When subjects choose their own treatment (are self-selected into treatments based on their varying compliance with assignment to treatment states), many of the well-developed techniques of randomization-based experimental design and analysis are no longer applicable. With random assignment to treatment and control conditions, we can reasonable assume that over many replications, the two groups will be similar in all respects (observed and not observed) but that of receiving the treatment. With non-random assignment, it may be true that the groups differ on the variable of interest prior to receiving the treatment, and that a measured post-treatment difference (or lack thereof) will be erroneously attributed to the treatment. Our approach involves making all subjects aware of the availability of the treatment, but then offering extra encouragement (an encouragement design) to participate in the treatment to a randomly selected half of the population. If the encouragement is successful, we show how this leads to an estimable treatment effect (with associated asymptotic standard error).An illustrative example using fictitious data is presented in which we measure the effects of coupon books on store purchase behavior. A randomly selected half of the customers at a given store are assigned to receive coupon books as part of a package of store materials (the treatment condition) whereas the other half are not. We overlay on this initial randomized design an encouragement condition in which a second randomly chosen half of the store's customers receive their materials from an employee (encouraging participation with the treatment), and for the other half the materials were simply placed on a table. The market share of persons who chose to take the coupon book was 44% and 20% from those who did not. A naive estimate of the effect of the treatment is 24%; however this estimate ignores the self-selection bias (those persons assigned to receive the coupon book but refused to take it, and those not assigned who picked one up anyway). Using the encouragement design estimator derived leads to a lower estimated impact of the treatment at 5%. The difference in these results may have significant impact on the choice by store management to utilize employees to hand out promotional materials.Eric T. Bradlow is Assistant Professor of Marketing and Statistics     

Testing a parametric quantile-regression model with an endogenous explanatory variable against a nonparametric alternative

This paper is concerned with inference about a function g that is identified by a conditional quantile restriction involving instrumental variables. The paper presents a test of the hypothesis that g belongs to a finite-dimensional parametric family against a nonparametric alternative. The test is not subject to the ill-posed inverse problem of nonparametric instrumental variable estimation. Under mild conditions, the test is consistent against any alternative model. In large samples, its power is arbitrarily close to 1 uniformly over a class of alternatives whose distance from the null hypothesis is proportional to n^−1/2, where n is the sample size. Monte Carlo simulations illustrate the finite-sample performance of the test.     

世贸组织框架下我国农业保护的现实选择

入世对我国来说是一把“双刃剑”,有机遇也有挑战。在农业尤其是农产品国际贸易这一领域,入世的冲击是十分显著的。本文根据世界贸易组织的要求和有关经济理论,对入世后我国农业保护的现实选择问题进行了研究,重点探讨了差价补贴这一新方法,进而提出了相应的政策建议。     

Regret minimization in repeated matrix games with variable stage duration

Regret minimization in repeated matrix games has been extensively studied ever since Hannan's seminal paper [Hannan, J., 1957. Approximation to Bayes risk in repeated play. In: Dresher, M., Tucker, A.W., Wolfe, P. (Eds.), Contributions to the Theory of Games, vol. III. Ann. of Math. Stud., vol. 39, Princeton Univ. Press, Princeton, NJ, pp. 97–193]. Several classes of no-regret strategies now exist; such strategies secure a long-term average payoff as high as could be obtained by the fixed action that is best, in hindsight, against the observed action sequence of the opponent. We consider an extension of this framework to repeated games with variable stage duration, where the duration of each stage may depend on actions of both players, and the performance measure of interest is the average payoff per unit time. We start by showing that no-regret strategies, in the above sense, do not exist in general. Consequently, we consider two classes of adaptive strategies, one based on Blackwell's approachability theorem and the other on calibrated play, and examine their performance guarantees. We further provide sufficient conditions for existence of no-regret strategies in this model.     

Class-size effects in school systems around the world: Evidence from between-grade variation in TIMSS

We estimate the effect of class size on student performance in 11 countries, combining school fixed effects and instrumental variables to identify random class-size variation between two adjacent grades within individual schools. Conventional estimates of class-size effects are shown to be severely biased by the non-random placement of students between and within schools. While we find sizable beneficial effects of smaller classes in Greece and Iceland, we reject the possibility of even small effects in four countries and of large beneficial effects in an additional four countries. Noteworthy class-size effects are observed only in countries with relatively low teacher salaries.     

国际商品市场中"一价定律"的验证:共同概率模型和动态贸易变量

本文讨论并引伸了Barrett和Li(2002)提出的共同概率模型,在原有基础上将贸易变量动态化,以增加在经验分析中所包含的信息量和解释能力。考虑到国际商品贸易的跨期性,我们的预期价格采用了商品期货价。我们用改进后的方法对中美大豆贸易做了实证分析,发现两国大豆市场自1995年以来基本上是整合的,并发现对竞争性均衡关系的偏离主要发生在早期,即在中国商品期货市场完善和农产品市场体制改革之前。研究还发现两国大豆价差在南美豆收获期后明显缩小。收益不确定性参数的t检验不显著在一定程度上表明了进口商对价格风险的规避行为。     

完全成本法和变动成本法的比较应用——基于存货的发出计价方式

完全成本法和变动成本法在企业成本计算方面各有侧重，其常用的理论结论证明常常被运用，在企业实践中能否适用？本文主要通过企业案例进行实用性的论证。     

On the optimality of proportional reinsurance

Proportional reinsurance is often thought to be a very simple method of covering the portfolio of an insurer. Theoreticians are not really interested in analysing the optimality properties of these types of reinsurance covers. In this paper, we will use a real-life insurance portfolio in order to compare four proportional structures: quota share reinsurance, variable quota share reinsurance, surplus reinsurance and surplus reinsurance with a table of lines.     

Using a four-step heuristic algorithm to design personalized day tour route within a tourist attraction

The design of personalized day-tour routes for tourists plays a fundamental role in improving tourists’ travel experiences, and it is a crucial practice for managers of tourist attractions in an increasingly competitive marketplace. This study constructs a tourist recommendation system with consideration for aesthetic fatigue and variable sightseeing value. A four-step heuristic algorithm (involving a genetic algorithm and a difference evolution algorithm) is proposed, which serves as the nucleus for a new system to deal with the tourist trip design problem. To evaluate the performance of this algorithm, a case study was conducted at the Jiuzhai Valley in Sichuan, China. The results of paired sample t-tests indicated that the proposed heuristic algorithm indeed performed significantly better than existing methods. Furthermore, the study showed that our proposed system was able to design more realistic and better personalized routes for tourists than previous systems.