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.     

Why I am a Psychology Major: An Empirical Analysis of Student Motivations

The underlying “architecture of the decision to pursue a degree in psychology was quantified using the Method of Sorting technique to identifying the critical issues necessary to make this choice. Multidimentsional scaling procedures were employed to construct a three-dimensional map representing the relationships between reasons for selecting psychology as a major. Freshman and senior psychology majors (N = 165) from a regional university and a large research-based institution rated the relative importance of items in their decision-making process. Hierarchical clustering procedures revealed seven different groups of students. Although significant differences associated with class standing were not found, institutional affiliation did influence cluster composition. Reflecting local emphases, students at the regional institution had a greater interest in Counseling Psychology, whereas those at the research-based school focused on Clinical Psychology. This semantic map and the associated item clusters arising from psychology student data provides an empirical basis for, amongst other things, course selection, faculty-initiated program design or revision, strategic niche marketing, and student retention.     

Memory recall errors in retrospective surveys: A reverse record check study

This paper reports on a study to compare self-reports during an interview with staff who attended a University health centre in Turkey, with the records of visits to the same health centre over the previous 12 months. Design of the study reflects the effects of importance of the event, duration since the event, frequency of the occurrence of the event, measurement scale of the event, and bounded and unbounded recalling. In order to assess the extent of recall error, responses to retrospective questions on health centre visits are compared with administrative records. Statistical models are proposed for short and long term human memory recall error effects on responses.     

The causal relation between government revenue and spending: Evidence from Egypt and Jordan

In investigating the causal relation between government revenue and spending, our empirical results support the tax-and-spend hypothesis for Egypt and the fiscal synchronization hypothesis for Jordan. Breaking away from these historical trends is essential for both countries to eliminate the budget deficit and therefore ensure the availability of domestic saving for private investment. To cope with unemployment and poverty, continuing privatization is recommended for both countries to improve productivity and efficiency in the domestic economy. Privatization should lead to higher domestic saving and investment and at the same time eliminate the budget deficit by enhancing revenue and curbing spending. (JEL H62, H63)     

物流中的新设施—自动化立体仓库

当今物流速度日益加快，仓库建设和改造向空间、立体化、自动化快速发展，建设自动化立体仓库是今后的必然趋势。结合多年实践．对物流领域成件货物储存的新设施，自动化立体仓库进行了详细阐述。     

Nash-equilibria in a heterogeneous oligopoly with fuzzy information

We consider a model of an oligopolistic market with heterogeneous firms and products where neither the cost nor the demand functions are common knowledge. Instead, each firm only has some vague ideas about the price strategies adopted by its competitors which is modelled by a fuzzy set. In analogy to the notion of an "equilibrium of actions and beliefs" we define and characterize a generalized Nash-equilibrium and show its existence under general conditions. Furthermore, the impact of the fuzzy information on the equilibrium outcome is analyzed by means of a comparative static analysis within a particular model framework.Received: 28 May 2002, Accepted: 25 December 2002, JEL Classification: D43, D80, L13We wish to thank Bernhard F. Arnold, the editor Murat Sertel , and two anonymous referees for helpful comments. Of course, we are responsible for all remaining errors.     

A note on the determination of A-optimal type block designs under fixed and mixed effects models

In this paper, we consider the problem of estimating a selected set of contrasts between v treatments using a block design consisting of b blocks of size k. Traditionally, the construction of A-optimal block designs for such situations has been carried out assuming a fixed effects model. In this paper, we show that A-optimal designs constructed under a fixed effects model are robust in the sense that these designs have maximal minimal efficiency when considered among all available designs and under all possible mixed effects models. AMS 1991 subject classifications: Primary 62K05; Secondary 62K10     

Duration dependence testing for speculative bubbles

Prior research has employed a number of methods to test for speculative bubbles in asset prices, including a method based on the concept of duration dependence. This study explores whether duration dependence tests for speculative bubbles are sensitive to specification decisions. Our results question the efficacy of using measures of duration dependence to test for speculative bubbles. In particular, we find that evidence of duration dependence is sensitive to the method of correcting for discrete observation of continuous duration, the use of value-weighted versus equally weighted portfolios, and the use of monthly versus weekly runs of abnormal returns. (JEL C41, G12)     

团队合作中的利益分配机制及其调整过程探讨

本文主要探讨团队合作这种新兴工作机制的利益分配机制,首先提出了两种方法:其一,权的最小平方法,建立在专家评分基础之上,具有一定的主观性;其二,在合作博弈框架之上运用Shapley定理确定分配方案,具有较好的客观性、公正性。本文后一部分主要讨论在使用Shapley定理确定分配方案之后的团队博弈,即一旦团队由合作博弈进入非合作博弈后,团队利益分配是如何进行调整的,以及调整过程中博弈双方的策略变化和这种调整产生的内在机理。     

医学学生临床技能培训的探讨

探讨强化临床医学专业学生实践技能方法，提高医学生临床应用能力和技能操作水平，提高医院带教老师和病人对学生的满意度。选择2003级临床医学专业43名学生为研究对象，设计实习前强化训练内容和方法，逐项进行训练，随机抽样测试并对比强化训练前后学生技能成绩。通过实习前强化训练，学生体格检查技能成绩、病历书写及医嘱等合格率与强化训练前相比有显著的差异性（P〈0．01）。对医学生开展实习前强化训练，是提高医学生临床应用能力及实践技能水平的有效方法，具有一定的实用价值。