SELECTION BIAS CORRECTIONS BASED ON THE MULTINOMIAL LOGIT MODEL: MONTE CARLO COMPARISONS

Abstract.  This survey presents the set of methods available in the literature on selection bias correction, when selection is specified as a multinomial logit model. It contrasts the underlying assumptions made by the different methods and shows results from a set of Monte Carlo experiments. We find that, in many cases, the approach initiated by Dubin and MacFadden (1984) as well as the semi-parametric alternative recently proposed by Dahl (2002) are to be preferred to the most commonly used Lee (1983) method. We also find that a restriction imposed in the original Dubin and MacFadden paper can be waived to achieve more robust estimators. Monte Carlo experiments also show that selection bias correction based on the multinomial logit model can provide fairly good correction for the outcome equation, even when the IIA hypothesis is violated.     

Developing a tutoring module for presentation of computerized patient management problems

The simulation problem is one of the most commonly used formats in computer-assisted instruction (CAI). In medical education, a patient simulation problem is known as a patient management problem (PMP). A number of computerized PMP systems are currently available. However, to date, there is no record of PMP systems having been developed using artificial intelligence. This is noteworthy since artificial intelligence techniques could help in the generation of more effective and intelligent instructional systems.

This paper analyzes and evaluates existing instructional simulation software in clinical medicine in terms of effective educational design attributes. Components of effective PMP systems thus identified are incorporated into a computerized instructional system which uses artificial intelligence techniques for teaching problem-solving and diagnostic skills to undergraduate medical students.     

美国的城市化进程与现代城市规划联系的解读

回顾了美国城市化的独特发展历程和美国现代城市规划历史,并就二者之间的相互关系进行了探讨,以期对处于转型期的中国城市化发展有所启示和借鉴.     

城市交通与城市空间结构演变

通过回顾城市交通和城市空间结构的发展演变过程,研究通过城市交通引导城市空间结构健康"生长"的有效途径,提出通过公共交通引导城市发展的TOD模式,以及适合中国特色的和谐城市形态和城市交通.     

Religion and International Trade: Does the Sharing of a Religious Culture Facilitate the Formation of Trade Networks?

A bstract .   Despite interest in the influence of religion on economic activity by early economists like Adam Smith, modern economists have done little research on the subject. In light of the apparent religious fervor in many parts of the global economy, economists' seeming lack of interest in studying how religious cultures enhance or retard the globalization of economic activity is especially surprising. This article makes a contribution toward filling this void by examining how religion affects international trade. Specifically, we examine whether the sharing of religious cultures enables the formation of exchange networks that can overcome the failure or nonexistence of other social and economic institutions necessary for completing complex international transactions. We apply an expanded gravity model of international trade to control for a variety of factors that determine trade, and we use two recently developed regression methods, scaled OLS and nonlinear least squares, to exploit the model to its fullest. We find that the sharing of Buddhist, Confucian, Hindu, Eastern Orthodox Catholic, and Protestant cultures by people in different countries has a significantly positive influence on bilateral trade, all other things equal. The sharing of Roman Catholic culture has a significantly negative influence on bilateral trade, and the sharing of Islamic and Judaic cultures neither promotes nor discourages international exchange. These results suggest that some religious cultures are more conducive than others for forming international trade networks.     

中国政策性创业资本的地位及定位研究

文中将创业资本划分为政策性创业资本与商业性创业资本,提出政策性创业资本不应以追求商业利润或与私人部门分享利润为目标,而是以税收、就业、区域发展、出口和经济发展作为追求目标。它应该承担起更多的社会功能,政策性创业资本的定位就在于通过国家宏观政策方面的调节来分散、分担商业性创业资本的经营风险,吸引、引导、鼓励、扶持商业资本进入创业投资领域。     

浅谈企业信用风险管理

社会主义经济是信用经济,没有信用,就没有秩序,市场经济就不能健康的发展。加强企业信用管理的风险控制是现代企业的一项重要任务。进入WTO标志着中国经济更加开放,国际贸易更加纷繁复杂,在机遇透人的同时,企业也潜伏着越来越大的风险,尤其是企业信用风险。因此强化企业的信用风险管理,建立与完善企业内部信用风险管理体制,仍然是企业面临的一项重要课题,笔者从多方面阐述了企业信用风险形成的原因以及如何建立风险管理机制等问题。     

浅析我国"红顶商人"现象

“红顶商人”是市场经济不成熟的产物。“红顶商人”与民争利 ,利用特权敛聚财富 ,不但严重破坏市场经济秩序而且滋生政治腐败。要彻底清除“红顶商人”现象 ,应采取促进民主政治建设、制定“国家公务员法”、规范行业协会行为、增加地方财政收入和加强监督力度等有力措施。