GMM with many weak moment conditions: Replication and application of Newey and Windmeijer (2009)

In a recent article Newey and Windmeijer (Generalized method of moments with many weak moment conditions. Econometrica 2009; 77 (3): 687–719) propose a new variance estimator for generalized empirical likelihood. In Monte Carlo examples they show that t‐statistics based on the new variance estimator have nearly correct size. I have replicated their Monte Carlo simulations and in addition used the new variance estimator to re‐estimate Angrist and Krueger's (Does compulsory school attendance affect schooling and earnings? Quarterly Journal of Economics 1991; 106 (4): 979–1014) returns to education. Copyright © 2011 John Wiley & Sons, Ltd.     

Using Compulsory Mobility to Identify School Quality and Peer Effects

Education production functions that feature school and student fixed effects are identified using students' school mobility. However, student mobility is driven by factors like parents' labour market shocks and divorce. Movers experience large achievement drops, are more often minority and free meal students, and sort endogenously into peer groups and school types. We exploit an English institutional feature whereby some students must change schools between grades 2 and 3. We find no evidence of endogenous sorting of such compulsory movers across peer groups or school types. Non‐compulsory movers bias school quality estimates downward by as much as 20% of a SD.     

THE EFFECTS OF COMPANY TRAINING,FURTHER EDUCATION AND THE YOUTH TRAINING SCHEME ON THE EARNINGS OF YOUNG EMPLOYEES*

Abstract This paper provides evidence on the impact of company training, of post-compulsory education and of the UK Youth Training Scheme in the late 1980's on the earnings of 21-year-old employees in England and Wales. Earnings equations are estimated for each of seven groups of employees who have followed alternative routes from compulsory education into employment, allowing for selectivity into these routes. There are several findings, including: both high parental social class and better school qualifications help to channel people into higher status routes, while high local unemployment has the opposite effect; participation in company training in long spells substantially raises wages but short spells do not; YTS participation fails to raise, and possibly substantially lowers, wages even three years after graduation compared to those who left school at 16 and went to work and received no training; there is weak evidence that, even for those that do not enter higher education, it is better to stay on at school after 16 than go into YTS.     

Does attending predominately-female schools make a difference? Labor market outcomes for women

This study explores the effects of attending predominately-female high schools on labor market outcomes. The existing literature about these schools is quite limited, and most research focuses on role-model effects at coeducational schools. Since returns to predominately-female high school attendance are likely to be upward biased due to selection, data from the National Longitudinal Survey of Youth are used to explore the determinants of such attendance. Girls who are raised Catholic, who are nonwhite, or who live in urban areas are more likely to enroll in predominately-female schools. Though women who attended these schools are no more or less likely to enter the workforce, they do earn a 19.7% higher wage than women who attended coeducational high schools. Controlling for personal characteristics as well as selection into predominately-female schools and into the workforce, the estimated wage differential falls to 12.6%.     

Does federal financial aid affect college enrollment? Evidence from drug offenders and the Higher Education Act of 1998

In 2001, amendments to the Higher Education Act made people convicted of drug offenses ineligible for federal financial aid for up to two years after their conviction. Using rich data on educational outcomes and drug charges in the NLSY 1997, we show that this law change had a large negative impact on the college attendance of students with drug convictions. On average, the temporary ban on federal financial aid increased the amount of time between high school graduation and college enrollment by about two years, and we also present suggestive evidence that affected students were less likely to ever enroll in college. Students living in urban areas are the most affected by these amendments. Importantly, we do not find that the law deterred young people from committing drug felonies nor did it substantively change the probability that high school students with drug convictions graduated from high school. We find no evidence of a change in college enrollment of students convicted of non-drug crimes, or of those charged by not convicted of drug offenses. In contrast to much of the existing research, we conclude that, for this high-risk group of students, eligibility for federal financial aid strongly impacts college investment decisions.     

How Does Education Affect the Earnings Distribution in Urban China?*

It is widely believed that investing in education could be an effective strategy to promote higher standards of living and equity. We empirically assess this claim by estimating returns to education across the whole earnings distribution in urban China and find supporting evidence. In particular, we find that returns to education are more pronounced for individuals in the lower tail of the distribution than for those in the upper tail and that returns to education are uniformly larger for women than men. We also find that returns to education increased over time across the whole earnings distribution.     

Closing schools in a shrinking district: Do student outcomes depend on which schools are closed?

In the last decade, many cities around the country have needed to close schools due to declining enrollments and low achievement. School closings raise concerns about the possible negative impacts on student achievement, neighborhoods, families, and teaching staff. This study examines an anonymous urban district that, faced with declining enrollment, chose to make student achievement a major criterion in determining which schools would be closed. The district targeted low-performing schools in its closure plan, and sought to move their students to higher-performing schools. We estimate the impact of school closures on student test scores and attendance rates by comparing the growth of these measures among students differentially affected by the closures. We use residential assignment to school as an instrument to address non-random sorting of students into new schools. We also statistically control for the contemporaneous effects of other reforms within the district. Results show that students displaced by school closures can experience adverse effects on test scores and attendance, but these effects can be minimized when students move to schools that are higher-performing (in value-added terms). Moreover, the negative effect on attendance disappears after the first year in the new school. Meanwhile, we find no adverse effects on students in the schools that are receiving the transferring students.     

A finite‐sample hierarchical analysis of wage variation across public high schools: evidence from the NLSY and high school and beyond

Using data from both the National Longitudinal Survey of Youth (NLSY) and High School and Beyond (HSB), we investigate if public high schools differ in the “production” of earnings and if rates of return to future education vary with public high school attended. Given evidence of such variation, we seek to explain why schools differ by proposing that standard measures of school “quality” as well as proxies for community characteristics can explain the observed parameter variation across high schools. Since analysis of widely‐used data sets such as the NLSY and HSB necessarily involves observing only a few students per high school, we employ an exact finite sample estimation approach. We find evidence that schools differ and that most proxies for high school quality play modest roles in explaining the variation in outcomes across public high schools. We do find evidence that the education of the teachers in the high school as well as the average family income associated with students in the school play a small part in explaining variation at the school‐level. Copyright © 2002 John Wiley & Sons, Ltd.     

Mandatory summer school and student achievement

Using administrative data from a large school district, I exploit the fact that students are mandated to attend summer school based on a discontinuous function of their score on year-end exams to identify the effect of summer school attendance on achievement. I find an average effect of about .12 standard deviations for both math and reading achievement, an effect size on the low end of the range of prior estimates. These averages mask considerable heterogeneity, however, with effect size estimates ranging from just below zero to one-quarter of a standard deviation. The estimates on the upper end of the range presented here suggest that summer school may be a more cost-effective way of raising student achievement scores than class-size reductions.     

高收缴矛盾下的贫困生管理与服务

对贫困大学生的资助,备受中央和百姓的关注,日益成为炙手可热的话题。我院是国家示范性软件学院,收费高,收缴矛盾更为突出。近年来,我院在贫困生资助方面做了大量有益的探索,也感受到其中的艰辛。本文之意在于通过介绍我们的一些做法,抛砖引玉,引起同行们的共鸣与交流。     

Natural conjugate priors for the instrumental variables regression model applied to the Angrist–Krueger data

We propose a natural conjugate prior for the instrumental variables regression model. The prior is a natural conjugate one since the marginal prior and posterior of the structural parameter have the same functional expressions which directly reveal the update from prior to posterior. The Jeffreys prior results from a specific setting of the prior parameters and results in a marginal posterior of the structural parameter that has an identical functional form as the sampling density of the limited information maximum likelihood estimator. We construct informative priors for the Angrist–Krueger [1991. Does compulsory school attendance affect schooling and earnings? Quarterly Journal of Economics 106, 979–1014] data and show that the marginal posterior of the return on education in the US coincides with the marginal posterior from the Southern region when we use the Jeffreys prior. This result occurs since the instruments are the strongest in the Southern region and the posterior using the Jeffreys prior, identical to maximum likelihood, focusses on the strongest available instruments. We construct informative priors for the other regions that make their posteriors of the return on education similar to that of the US and the Southern region. These priors show the amount of prior information needed to obtain comparable results for all regions.     

Reanalyzing Zero Returns to Education in Germany

Pischke and von Wachter (Review of Economics and Statistics 2008; 90 (3): 592–598) find zero earnings returns to compulsory schooling in the basic school track in Germany. We reanalyze their study using a different dataset. In an extension, we use additional instruments which allow estimation of heterogeneous effects for different groups of compliers. We can confirm the previous result and also find zero returns for other compliers in higher track schools. Moreover, we do not find a causal effect of schooling on cognitive skills. This is in line with a potential reason Pischke & von Wachter (2008) give for their result, namely that basic skills are learned earlier in Germany and additional years of schooling are no longer effective. Copyright © 2015 John Wiley & Sons, Ltd.     

The Effect of School Size on Exam Performance in Secondary Schools

This paper investigates the relationship between school size and the exam performance of school pupils in their final year of compulsory education. Previous studies of this relationship have been seriously constrained by lack of appropriate data, but the publication of the School Performance Tables for all publicly-funded schools in England since 1992 permits the construction and testing of a multivariate model which includes school size as one of the explanatory variables. After controlling for factors such as type of school, teaching inputs and eligibility for free school meals, the partial effects of school size on exam performance are estimated. The primary result is that there is a non-linear relationship (in the form of an inverted-U) between school size that maximizes the exam performance of schools is estimated to be about 1,200 for 11–16 schools and 1,500 for 11–18 schools. These estimates are considerably higher than the current mean size of schools.     

在物理教学中学生创新能力的培养

在课程改革和义务教育物理教材改革的过程中,通过义务教育阶段的物理学习,使学生能够具有初步的创新精神和创新能力的创新教育已成为物理教学的一个重点,在实际教学过程中对学生创新能力的培养,已引起广大物理教师的高度重视,如何培养学生创新能力,找到培养和发展学生创新能力的有效途径,在物理教学中愈来愈显得重要。本人在具体的物理教学过程中,注重了学生创新能力的培养。     

小学数学教学与德育工作的有效整合

义务教育阶段的数学课程的出发点是促进学生全面、持续、和谐地发展。结合数学课程进行德育教育是我国中小学数学课程目标的一个显著特点。在使用新教材的背景下,如何将数学课堂教学与德育工作有效整合？就此,笔者结合教学实践就数学课程课堂教学过程、教学内容、学习方式与德育工作的有效整合总结自己的做法。     

为高中留学生开启一扇化学之门

设立高中留学生班是广西华侨学校开拓华文教育的重要举措,也是把该校高中办成特色高中的有机组成部分,更是海外侨社侨团、学生家长的殷切期盼,有着重大的现实意义和深远的历史意义。文章从化学用语的引入、实验教学、趣味教学、兴趣培养、因材施教等方面来论述如何为高中留学生开启一扇化学之门。     

CONDITIONALLY HETEROSKEDASTIC FACTOR MODELS WITH SKEWNESS AND LEVERAGE EFFECTS

Conditional heteroskedasticity, skewness and leverage effects are well‐known features of financial returns. The literature on factor models has often made assumptions that preclude the three effects to occur simultaneously. In this paper I propose a conditionally heteroskedastic factor model that takes into account the presence of both the conditional skewness and leverage effects. This model is specified in terms of conditional moment restrictions and unconditional moment conditions are proposed allowing inference by the generalized method of moments (GMM). The model is also shown to be closed under temporal aggregation. An application to daily excess returns on sectorial indices from the UK stock market provides strong evidence for dynamic conditional skewness and leverage with a sharp efficiency gain resulting from accounting for both effects. The estimated volatilitypersistence from the proposed model is lower than that estimated from models that rule out such effects. I also find that the longer the returns' horizon, the fewer conditionally heteroskedastic factors may be required for suitable modeling and the less strong is the evidence for dynamic leverage. Some of these results are in line with the main findings of Harvey and Siddique ( 1999 ) and Jondeau and Rockinger ( 2003 ), namely that accounting for conditional skewness impacts the persistence in the conditional variance of the return process. Copyright © 2012 John Wiley & Sons, Ltd.     

The effects of families and ability on men's education and earnings in Britain

The paper estimates the returns to education for a cohort of men born in Britain in March 1958 who have been followed since birth until the age of 33. The data used has a wealth of information on family background including parental education, social class and interest shown in the child's education as well as measures of ability. These variables are typically missing in studies looking at the returns to schooling. In the paper, we find that the average return to an additional year of full-time education for the UK men is somewhere around 5 1/2% to 6% even after correcting for the effects of measurement error. The paper also presents evidence that the returns to an additional year of schooling in the UK are heterogeneous. In particular, the paper finds some evidence that men with lower tastes for education, have significantly higher marginal returns to education. The results of the paper suggest that recent IV estimates of the returns to schooling in the UK, which exceed typical OLS estimates, may overestimate the average marginal return for the population of men as a whole.     

激活高中英语课堂 提高课堂教学质量

课堂教学是教师对学生进行素质教育的基本途径和主要形式。针对传统高中英语课堂教学中存在的问题,激活英语课堂,使其成为一个开放、互动、有序、善思、高效的新型课堂,对提高英语课堂教学质量具有非常重要的意义。     

The Quality of Data Obtained from Self-Completed Questionnaires in a Survey of High School Students

This study examines issues of data quality in a survey conducted in a nationwide probability sample of 8985 students in the last four years of high school education in Greece. Respondents completed an extensive questionnaire whose main topic of investigation was the use of licit and illicit substances (tobacco, alcohol, cannabis, etc.). We examined the effect of sex, age and school performance on data quality. Specifically, we related these factors to the probabilities of correctly observing filters in the questionnaire, of certain inconsistencies in responses, of reporting difficulty in understanding the questions and being able to answer honestly. It was found that all these factors have strong effects. Boys’ responses presented more problems than girls’ (median odds ratio in a series of separate logistic regressions = 1.35) and younger respondents’ more than older (median odds ratio 1.34 for ages 13–14 and 1.06 for ages 15–16, compared to ages 17–18). The strongest effect was related to school performance compared to the best students (school marks 18–20), median odds ratios were 1.31 for marks 15–17, 1.76 for 12–14 and 3.25 for 10–11. Implications for questionnaire design are discussed.