A play-the-winner-type urn design with reduced variability

We propose a new adaptive allocation rule, the drop-the-loser, that randomizes subjects in the course of a trial comparing treatments with dichotomous outcomes. The rule tends to assign more patients to better treatments with the same limiting proportion as the randomized play-the-winner rule. The new design has significantly less variable allocation proportion than the randomized play-the-winner rule. Decrease in variability translates into a gain in statistical power. For some values of success probabilities the drop-the-loser rule has a double advantage over conventional equal allocation in that it has better power and assigns more subjects to the better treatment. Acknowledgments. I thank Stephen Durham, the associate editor, and the referees for their helpful suggestions.     

城市科学20年的发展历程--祝贺中国城市科学研究会成立20周年

回顾北京市城市科学研究会的发展历程,分为多学科协同研究城市问题阶段;城市发展多学科综合研究阶段;城市发展综合研究向重点领域开展阶段.概括了北京城科会的主要学术成果.     

正交实验设计方法在B to B电子商务体系质量改进中的应用

电子商务在全球快速地发展，中国企业面临着由B to C方式向B to B方式的转变，本文采用正交实验设计的方法来解决已建成电子商务体系的质量，以满足新的需求。     

Self‐help in housing and chengzhongcun in China's urbanization

This article focuses on the housing issues of rural migrants arising from urbanization, with particular reference to chengzhongcun, a topic with considerable impact on policymaking. An attempt is made to understand the underlying rationale of self‐help in housing and the important role of chengzhongcun in sheltering rural migrants in the context of China's rural‐urban dichotomy. As demonstrated in this study, chengzhongcun accommodate, with little in the way of government resources and assistance, millions of rural migrants because of their social accessibility and affordability. While not denying their social problems, we argue that chengzhongcun in fact act as an innovative and positive agent to promote urbanization in present day China by housing massive numbers of rural migrants and assimilating them into cities. Current government policies towards chengzhongcun have generated a wide range of interest conflicts and confrontations. The consequences of such conflicts show that the government policies were problematic and unworkable, as they violated basic market principles as well as citizen rights. Policy strategy towards the redevelopment of chengzhongcun must acknowledge their credibility in the Chinese road to urbanization and requires more thoughtful and prudent consideration of migrants' demands for affordable housing.     

Regional economic performance in China1

This paper investigates convergence patterns among China's provinces using GDP data for the period 1952–97. We analyze convergence behaviour on the basis of Markov chains proposed by Quah (1993 ) and the generalized entropy decomposition proposed by Shorrocks (1980, 1984 ). Both sets of results show similar evidence of convergence within the pre‐defined geo‐economic sub‐regions, but no evidence is found of convergence between the sub‐regions. This finding has important policy implications for regional economic development in China. JEL classification: C33, E20, O47.     

再论“三位一体”的农村改革观——农村管理模式的逻辑演进

历史上每一次土地制度、赋税制度和行政管理体制的较大规模变革,都是同步配套进行的,有其相互关联性和一般规律性.新中国成立后,在城乡对立的二元经济社会结构中,农村集体土地制度、农民收入分配制度和农村行政管理体制自成一体,封闭运行,城乡差别日益扩大,同时附带了明显的"外部性"问题.改革开放以来,国家新的农村政策导向和农村新经济因素的产生,正在促使中国经济社会结构由农村农业、城市工业的二元结构向城市、小城镇、乡村多种产业组合和多样化的生活方式并存的三元结构转换,终将形成城乡一体化发展的新格局.农村集体土地制度、国民收入分配制度和国家行政管理体制,必须要按照社会主义市场经济发展的基本规律和城乡经济社会协调发展的新要求,进行一次最彻底的整体性配套改革.