RELIABILITY OF STATED PREFERENCES FOR CHOLERA AND TYPHOID VACCINES WITH TIME TO THINK IN HUE,VIETNAM

We examine the effect of giving respondents time to think about their stated choices (SC) in a survey of cholera and typhoid vaccine preferences in Hue, Vietnam. Because neither vaccine is widely available in Vietnam, we used the SC approach (a stated preference technique) and gave half of our respondents overnight to think about their choices to make the hypothetical valuation scenario as similar to a real‐life choice situation as possible. Respondents who were given extra time made fewer choices that violated internal validity tests of utility theory, and had lower average willingness to pay (WTP), confirming a result found in similar studies in the contingent valuation literature. (JEL D12, I18, C25)     

略论唐代的政治婚姻及其作用

政治婚姻是以婚姻为手段达到某种政治目的的婚姻形式 ,它是唐代政治、军事斗争的产物 ,其方式和类型也随政治、军事形式的变化而变化。在不同时期、不同条件下 ,政治婚姻所起的作用也不尽相同。唐政府与少数民族之间的和亲有利于边疆和平和双方的经济文化交流 ;朝廷与藩镇联姻有助于加强中央对地方的控制 ,维护中央集权 ;藩镇之间联姻在初期巩固了军事同盟和地方割据 ,至唐末又有助于壮大强藩的势力 ,实现局部的统一。     

试论人力资本投资理论与我国高等教育

利用人力资本理论探讨高等教育的发展以及中国现代化建设,提出高等教育投入产出的实质是人力资本投资过程。针对人力资本投资过程中所面临的问题,首先要确定高等教育的主体地位,其次根据国家、个人、企业团体的权益,建立起完善的高等教育成本分担理论。     

Bias Reduction of Likelihood Estimators in Semiparametric Frailty Models

Abstract. Frailty models with a non‐parametric baseline hazard are widely used for the analysis of survival data. However, their maximum likelihood estimators can be substantially biased in finite samples, because the number of nuisance parameters associated with the baseline hazard increases with the sample size. The penalized partial likelihood based on a first‐order Laplace approximation still has non‐negligible bias. However, the second‐order Laplace approximation to a modified marginal likelihood for a bias reduction is infeasible because of the presence of too many complicated terms. In this article, we find adequate modifications of these likelihood‐based methods by using the hierarchical likelihood.     

Perceptions of Drinking and Related Findings From the Nationwide Campuses Study

Abstract

Proponents of social norms approaches maintain that correcting misperceptions of alcohol use among college students may reduce drinking and its consequences. The author used aggregate campus-level data from the Nationwide Campuses Study to test this hypothesis. He defined the misperceptions ratio as the ratio of the frequency of the “average student's” perceived alcohol use to the frequency of self-use at each campus. Each of the 57 colleges reported misperceptions ratios greater than unity. At campuses where students had more accurate perceptions of alcohol use, students were more likely to desire alcohol availability at campus events and to drink on more days throughout the year than at campuses where students had greater misperceptions of alcohol use. The author found no data to support the preferential use of social norms programming on campuses with high levels of self-reported alcohol use or binge drinking. These findings raise questions about potentially unexpected and unintended effects of social norms approaches.