城市农民工歧视问题研究

采用中国住户调查数据和综合社会调查数据考察我国城市劳动力市场的户籍差异,并使用Oaxaca分解方法研究户籍歧视对差异的解释力度及其变动。研究表明,城市农民工无论在就业待遇还是就业保障方面均受到歧视。2002—2006年,农民工与城市工工资差异不断缩小,户籍歧视对工资的影响也相应降低;然而,农民工与城市工的就业保障差异在逐年扩大,户籍歧视的影响效应不断上升。     

Generalized discrete discrepancy and its applications in experimental designs

In recent years, there has been increasing interest in the study of discrete discrepancy. In this paper, the popular discrete discrepancy is extended to the so-called generalized discrete discrepancy. Connections among generalized discrete discrepancy and other optimality criteria, such as orthogonality, generalized minimum aberration and minimum moment aberration, are investigated. These connections provide strong statistical justification of generalized discrete discrepancy. A lower bound of generalized discrete discrepancy is also obtained, which serves as an important benchmark of design uniformity.     

从收入分配和经济发展的角度看我国的最低工资制度

本文基于我国的一些特殊的国情,从动态的视角出发,讨论了最低工资制度对我国收入分配格局和经济发展的影响.本文研究认为,由于我国特殊的国情,一种合适的最低工资制度在我国可能会产生以下三种效应:第一,最低工资制度具有改善我国收入分配格局,缩小收入差距的功能;第二,一个各地区有差别的最低工资限制可能会促进我国的产业结构向内地转移,促进我国的产业结构升级;第三,长期来看,最低工资限制可能会强制低人力资本工资进行人力资本投资,有助于我国人力资本的提升.     

市场状态依存的套期保值策略研究

最小方差套保策略没有考虑均值信息,没有考虑套保的成本和收益,不能区分买入套保和卖出套保。针对这一缺陷,本文在最小VaR套保策略框架下,提出了市场状态依存的套保策略,以区分买入套保和卖出套保,利用市场状态的信息来改善套保的财务表现。论文首先在理论上比较了市场状态依存策略与最小方差策略的套保比、套保的成本或收益,进一步基于铜期货市场、原油期货市场的数据实证比较了这两种策略的财务表现。理论和实证结果均表明：相对于最小方差套保策略,市场状态依存的买入套保策略的成本更低,卖出套保策略的收益更高;论文最后讨论了此策略的应用范围和局限性。     

Shifts in the employment outcomes among Mexican migrants to the United States, 1976–2009

Although studies have examined the impact of U.S. immigration policy shifts in the 1980s and 1990s on the employment outcomes of migrants, scholars have paid less attention to how the federal government's shifting approach to worksite enforcement has transformed the conditions in which Mexican migrants work. Consistent with previous research, we find a worsening of conditions for both unauthorized and legal Mexican migrants in the years following the passage of the Immigration Reform and Control Act (IRCA) and that unauthorized status is associated with more unfavorable workplace conditions relative to legal immigrants. However, in the first decade of the 21st century, we also find that unauthorized immigrants’ employment outcomes more closely resemble those of legal immigrants now than in the past, suggesting a dramatic shift in the ways that employers treat unauthorized immigrants on the job. This convergence between authorized and unauthorized migrants is consistent with federal policies and practices related to workplace enforcement.     

劳动力成本上升、加工贸易转移与企业出口附加值率攀升

中国出口国内附加值率（DVAR）持续攀升,伴随其上升的是用工成本的明显提高和加工贸易占比的显著下降,中国DVAR的提升究竟源于已有研究所指出的,投资自由化所带来的国内中间品对国外中间品的替代,即“主动”的提升？还是成本上升引致加工贸易不断退出市场的一个客观结果,即“被动”的提升？本文基于2000--2006年的微观数据,测算了企业层面的DVAR,从加工贸易退出的角度刻画了企业DVAR的动态演进过程,并进一步考察了最低工资所代理的劳动力成本、加工贸易与企业出口DVAR之间的关系。实证研究表明：最低工资所代理的劳动力成本上升会促使中国企业DVAR的攀升,这一结果在多个维度的稳健性检验中均是高度稳健的。最低工资上升对中国企业DVAR的促进作用通过引致加工贸易退出这一机制来实现。拓展性的研究还表明,最低工资上升对高生产率企业、外资企业和资本相对密集企业DVAR的正面促进作用更强。我们的发现意味着,中国DVAR的上升至少部分是加工贸易产业转移的结果,鼓励进口,同时促进国内中间品质量提升是我国现阶段发展的重要政策方向。     

Uniformity pattern and related criteria for q-level factorials

The objective of this paper is to study the issue of the projection discrepancy along the line of Liu (2002) and Fang and Qin (2005) based on discrete discrepancy measure proposed in Qin and Fang (2004), which has wide application to the field of fractional factorials. Here we also study the projection properties for q-level factorials and provide connection between minimum projection uniformity and other optimality criteria. A lower bound to projection discrepancy for q-level factorials is presented here.     

Adaptive Isotonic Estimation of the Minimum Effective and Peak Doses in the Presence of Covariates

We consider a problem of estimating the minimum effective and peak doses in the presence of covariates. We propose a sequential strategy for subject assignment that includes an adaptive randomization component to balance the allocation to placebo and active doses with respect to covariates. We conclude that either adjusting for covariates in the model or balancing allocation with respect to covariates is required to avoid bias in the target dose estimation. We also compute optimal allocation to estimate the minimum effective and peak doses in discrete dose space using isotonic regression.