Uniform Inference on Quantile Effects under Sharp Regression Discontinuity Designs

ABSTRACT

This study develops methods for conducting uniform inference on quantile treatment effects for sharp regression discontinuity designs. We develop a score test for the treatment significance hypothesis and Wald-type tests for the hypotheses related to treatment significance, homogeneity, and unambiguity. The bias from the nonparametric estimation is studied in detail. In particular, we show that under some conditions, the asymptotic distribution of the score test is unaffected by the bias, without under-smoothing. For situations where the conditions can be restrictive, we incorporate a bias correction into the Wald tests and account for the estimation uncertainty. We also provide a procedure for constructing uniform confidence bands for quantile treatment effects. As an empirical application, we use the proposed methods to study the effect of cash-on-hand on unemployment duration. The results reveal pronounced treatment heterogeneity and also emphasize the importance of considering the long-term unemployed.     

Nonparametric Estimation of Duration Dependence in Militarized Interstate Disputes

A militarized interstate dispute (MID) involves military conflict between states with diplomatic ties and exists because two or more states have failed to resolve their differences through diplomatic channels. Jones et al. (1996) characterize an MID as the threat, display or use of military force short of war. They analyze over 2000 disputes spanning two centuries across the globe and conclude that disputes tend to be persistent once established. In this paper, I find that the passage of time can be a favorable factor in dispute resolution, and thus historical mechanisms for dispute resolution favor ending, not extending, militarized disputes. I emphasize the use of non-parametric procedures first to estimate the hazard function and then to estimate the benefits of negotiated settlements.     

Semiparametric estimation of employment duration models

There are a variety of economic areas, such as studies of employment duration and of the durability of capital goods, in which data on important variables typically are censored. The standard techinques for estimating a model from censored data require the distributions of unobservable random components of the model to be specified a priori up to a finite set of parameters, and misspecification of these distributions usually leads to inconsistent parameter estimates. However, economic theory rarely gives guidance about distributions and the standard estimation techniques do not provide convenient methods for identifying distributions from censored data. Recently, several distribution-free or semiparametric methods for estimating censored regression models have been developed. This paper presents the results of using two such methods to estimate a model of employment duration. The paper reports the operating characteristics of the semiparametric estimators and compares the semiparametric estimates with those obtained from a standard parametric model.     

晚清传奇杂剧短暂中兴与消亡探因

晚清传奇杂剧在传统传奇杂剧极度衰微之时回光返照，短暂振起，顺应时势需要，注目现实社会，参与政治斗争，推动时代变革，为传统传奇杂剧的历史发展划上了较为圆满的句号。而自身的公式化、概念化、案头化的艺术弊病．对传统体制格律的若干不合时宜的背离，以及地方戏和新兴话剧之双重夹攻，则是晚清传奇杂剧终于未能保持振起之势而归于消亡的主要原因。     

复杂不确定环境下考虑代理人通过努力减少项目持续期限的最优代理合同

本文着重研究复杂不确定环境下如何设计最优合同,以激励代理人减少项目持续期限。在代理问题中,以往的数量研究大多使用随机变量刻画项目参数和代理人的努力程度。但是,在某些情况下,项目参数和代理人的努力程度不能被历史数据获得,而必须由专家进行估计。运用不确定变量刻画专家对这些参数的估计,并且证明这样做是合理的。通过应用不确定理论,提出复杂不确定环境下考虑代理人通过努力减少项目持续期限的最优代理合同模型。之后,为了解决这个问题,给出了该模型的确定性形式。此外,对是否考虑代理人不确定努力的最优合同进行了比较。结果显示,当其他条件相同时,委托人在考虑代理人不确定努力程度的合同中得到的期望收益不低于在没有考虑代理人不确定努力程度的合同中到的期望收益。最后,为了更好地展示模型的应用,给出了一个数值例子并进行了相关讨论。     

资源受限下平行工序顺序对优化的0-1规划模型

资源受限是工程项目时刻都可能面对的挑战。由于资源限制,需要将原项目计划中相互之间无优先关系的平行工序调整为顺序工序。平行工序顺序化可导致项目工期延迟,因此需考虑如何使项目工期延迟最小。该平行工序顺序优化问题是项目调度问题,也是排列组合问题,通常难度很大,包括一些NP-hard问题。本文主要研究该问题的一类典型子问题——平行工序顺序对优化,即如何将项目中某2n个平行工序调整为n个顺序工序对,并且对项目工期的影响最小。该问题的总方案数可达到（2n）!/n!。本文借助工序网络（如CPM网络）,运用简单的时间参数量化了平行工序顺序化对项目工期的影响,进而降低问题的求解难度,建立了纯0-1规划模型。实验验证了该模型的求解效率,求解100个平行工序规模的问题平均耗时0.2605秒,而求解500个平行工序规模的问题平均耗时10.66秒。     

The Association between head Start Enrollment and Children's Mental Health Scores

This study examined the association of the children's entry age and enrollment duration of Head Start on children's mental health, using secondary data analysis. Children were of three groups: one group of children entered Head Start at age 3 and maintained enrollment for 1 year (Group 1), the second group of children entered Head Start at age 4 and stayed for 1 year (Group 2) and the third group of children entered at age 3 and stayed in Head Start for 2 years (Group 3). Research questions are (1) Do child and family characteristics have any association with mental health scores? (2) Do children's mental health scores differ among the three groups? Compared with children who entered at age 4 and stayed for 1 year, children who entered Head Start at age 3 and stayed in Head Start both for 1 year and for 2 years had higher mental health scores. Controlling for other factors, boys and children with special needs had higher mental health scores. Black and dual bilingual children had lower mental health scores.     

“了”与“没（有）”共现句式的再考察

句尾“了”与副词“没（有）”共现句式,通常带有时段状语;而王灿龙认为,时段成分不是“了”与“没（有）”共现的必要条件。经考察得知,“了”与“没（有）”可以共现于不带时段状语的句子,但该类句子要有时量起始标记,或者有“就”、“再”等副词的介入。     

“有界时段”与“无界时段”

语言中的时间状语与动词之间的关系既是一个语法问题,也是一个认知问题。合乎语法正确的句子,不一定是合乎交际意义的句子。为此,通过分析"有界时段"(DTP:Defined Time Period)和"无界时段"(NTP:Non-defined Time Period),从认知角度讨论二者,即时间状语与动词之间的合理搭配问题。