The validity of survey responses on abortion: Evidence from Estonia

This paper presents results of a validation survey of abortion conducted in Tallinn, Estonia in April and May 1992. The sample was drawn from patient records in a maternity hospital. Women who had an abortion in that hospital in 1991 were asked about recent abortions as part of a survey about women’s health. More than 80% of the respondents reported having a recent abortion. Some respondents misreported their abortion as a miscarriage. Moreover, some variation in reporting was associated with respondents’ characteristics. Ethnic Estonians were less likely to report their abortion than were Russians, women over age 40 were less likely to report the abortion than younger women, and women who had the abortion late in the first trimester were less likely to report that abortion. There was some evidence that unmarried women were less likely than married women to report their abortion, and that women who had borne three or more children were less likely to report their abortion than women who had borne fewer children. These differences probably stem from the extent to which pregnancy or abortion is considered stigmatizing for women in different situations.     

Race and prevailing wage laws in the construction industry: Comment on Thieblot

Using the 1990 Census of Population, Thieblot (1999) argued that black employment and the strength of the prevailing wage laws are correlated and that repeal of these laws would lead to higher black employment in construction. Analysis of the 1970 Census of Population reveals that the relative abundance of black construction workers in the group of states that eventually would repeal their laws preceded those repeals and that this is mainly due to the characteristics of Southern labor markets. This and other research cast doubt on both the strength and the existence of such a correlation.     

Sampling Returns for Realized Variance Calculations: Tick Time or Transaction Time?

This article introduces a new model for transaction prices in the presence of market microstructure noise in order to study the properties of the price process on two different time scales, namely, transaction time where prices are sampled with every transaction and tick time where prices are sampled with every price change. Both sampling schemes have been used in the literature on realized variance, but a formal investigation into their properties has been lacking. Our empirical and theoretical results indicate that the return dynamics in transaction time are very different from those in tick time and the choice of sampling scheme can therefore have an important impact on the properties of realized variance. For RV we find that tick time sampling is superior to transaction time sampling in terms of mean-squared-error, especially when the level of noise, number of ticks, or the arrival frequency of efficient price moves is low. Importantly, we show that while the microstructure noise may appear close to IID in transaction time, in tick time it is highly dependent. As a result, bias correction procedures that rely on the noise being independent, can fail in tick time and are better implemented in transaction time.     

Optimal sampling for repeated binary measurements

The authors consider the optimal design of sampling schedules for binary sequence data. They propose an approach which allows a variety of goals to be reflected in the utility function by including deterministic sampling cost, a term related to prediction, and if relevant, a term related to learning about a treatment effect To this end, they use a nonparametric probability model relying on a minimal number of assumptions. They show how their assumption of partial exchangeability for the binary sequence of data allows the sampling distribution to be written as a mixture of homogeneous Markov chains of order k. The implementation follows the approach of Quintana & Müller (2004), which uses a Dirichlet process prior for the mixture.     

Classifying At‐Risk High School Youth: The Influence of Exposure to Community Violence and Protective Factors on Academic and Health Outcomes

Using cluster analysis, 789 predominately Latino and African American high school youth were classified into varying academic at‐risk profiles using self‐reported levels of academic confidence, motivation to attend school, perceived family support, connections with teachers and peers, and exposure to violence. Six clusters emerged, 5 of which were identified as “at‐risk.” The clusters were examined in relation to academic stress, health status, grades, and school retention. Exposure to violence was one distinguishing feature of youth identified as most vulnerable, vulnerable, and resilient; however, youth identified as resilient recorded better academic outcomes.     

科技传播研究:“普及范式”和“创新范式”

国内科技传播研究在近几年渐见繁荣之势。为了促进科技传播研究在国内更好地发展，文章讨论了已得到一定发展的“普及范式”和正在发展中的“创新范式”，认为面向未来知识经济的发展，需要推进“创新范式”的科技传播研究。     

发展和完善南宁市新型农村合作医疗制度研究

近年来,党和政府一直把发展和完善新型农村合作医疗制度作为改善民生的一项重要工作。南宁市新型农村合作医疗尽管有了较大的发展,但与同为西部省会城市的西安、昆明、成都相比还存在不少差距。这就需要结合地方实际,从运行机制、资金监管、信息化管理、人才建设等软、硬件方面破解新型农村合作医疗制度发展和完善的难题。     

Bayesian analysis of elapsed times in continuous‐time Markov chains

The authors consider Bayesian analysis for continuous‐time Markov chain models based on a conditional reference prior. For such models, inference of the elapsed time between chain observations depends heavily on the rate of decay of the prior as the elapsed time increases. Moreover, improper priors on the elapsed time may lead to improper posterior distributions. In addition, an infinitesimal rate matrix also characterizes this class of models. Experts often have good prior knowledge about the parameters of this matrix. The authors show that the use of a proper prior for the rate matrix parameters together with the conditional reference prior for the elapsed time yields a proper posterior distribution. The authors also demonstrate that, when compared to analyses based on priors previously proposed in the literature, a Bayesian analysis on the elapsed time based on the conditional reference prior possesses better frequentist properties. The type of prior thus represents a better default prior choice for estimation software.     

人力资源系统与公司绩效关系研究的测量误差：随机误差与系统误差

文章对人力资源系统与公司绩效关系实证研究中影响其效应大小的围绕项目、时间和评定者测量信度的随机误差和系统误差进行评述与分析,介绍基于构思水平理解评定者间信度的思路,较好解决了实证中的数据来源问题.并提出对管理感知这一新的系统误差的研究.总结改善信度的方法和探索,讨论了人力资源系统测量中需要改进的地方和进一步的研究方向.