SCHOOL QUALITY AND RETURNS TO EDUCATION OF U.S. IMMIGRANTS

Using the U.S. labor market as a common point of reference, this article investigates the influence of source country school quality on the returns to education of immigrants. Based on 1980 and 1990 census data, we first estimate country-of-origin specific returns to education. Results reveal that immigrants from Japan and northern Europe receive high returns and immigrants from Central America receive low returns. Next we examine the relationship between school quality measures and these returns. Holding per capita GDP and other factors constant, immigrants from countries with lower pupil-teacher ratios and greater expenditures per pupil earn higher returns to education.)     

Multiple paths in educational transitions: A multinomial transition model with unobserved heterogeneity

In many countries educational branching points consist of more than two qualitatively different alternatives, and only some alternatives provide the opportunity of continuing into higher education. I develop a multinomial transition model for modeling the effects of family background characteristics and individual characteristics on these complex educational careers. The model controls for unobserved heterogeneity that may, if ignored, result in biased estimates. Compared to previous research, I explicitly include instrumental variables that ensure identification of the unobserved component. I apply the model to the Danish case and analyze data which covers the educational careers of a cohort of Danes born around 1954. I find that the model brings forward non-trivial heterogeneity in the influence of family background and ability on qualitatively different choice alternatives both within and across transitions. I also find that not controlling for unobserved heterogeneity leads to marked underestimation of the family background effect on both early and late transitions in the educational career.     

Optimal detection of a jump in the intensity of a Poisson process or in a density with likelihood ratio statistics

We consider the problem of detecting a ‘bump’ in the intensity of a Poisson process or in a density. We analyze two types of likelihood ratio‐based statistics, which allow for exact finite sample inference and asymptotically optimal detection: The maximum of the penalized square root of log likelihood ratios (‘penalized scan’) evaluated over a certain sparse set of intervals and a certain average of log likelihood ratios (‘condensed average likelihood ratio’). We show that penalizing the square root of the log likelihood ratio — rather than the log likelihood ratio itself — leads to a simple penalty term that yields optimal power. The thus derived penalty may prove useful for other problems that involve a Brownian bridge in the limit. The second key tool is an approximating set of intervals that is rich enough to allow for optimal detection, but which is also sparse enough to allow justifying the validity of the penalization scheme simply via the union bound. This results in a considerable simplification in the theoretical treatment compared with the usual approach for this type of penalization technique, which requires establishing an exponential inequality for the variation of the test statistic. Another advantage of using the sparse approximating set is that it allows fast computation in nearly linear time. We present a simulation study that illustrates the superior performance of the penalized scan and of the condensed average likelihood ratio compared with the standard scan statistic.     

A Study of Alcohol Use by Designated Drivers Among College Students

Abstract

Objective: College students tend to drink while serving as a designated driver (DD). The predictors of alcohol use by DDs among college students were examined. Participants: Participants were 119 undergraduate students in introductory psychology courses who had experience with DD use. Methods: Survey data were analyzed to examine the predictors of planning components of DD use, such as choosing a DD before drinking and choosing an abstinent DD, and the relations of these components to alcohol use by DDs. Results: History of DD use, friends’ willingness to be the DD, frequency of riding with a driver who drank and drove, and age of drinking onset were associated with planning components of DD use. Among the planning components of DD use, choosing a DD before drinking was significantly related to less alcohol use by DDs. Conclusions: Increasing awareness of the planning components of DD use could deter alcohol use by DDs among college students.     

Incomplete equalization: The effect of tracking in secondary education on educational inequality

This paper tests whether the existence of vocationally oriented tracks within a traditionally academically oriented upper education system reduces socioeconomic inequalities in educational attainment. Based on a statistical model of educational transitions and data on two entire cohorts of Danish youth, we find that (1) the vocationally oriented tracks are less socially selective than the traditional academic track; (2) attending the vocationally oriented tracks has a negative effect on the likelihood of enrolling in higher education; and (3) in the aggregate the vocationally oriented tracks improve access to lower-tier higher education for low-SES students. These findings point to an interesting paradox in that tracking has adverse effects at the micro-level but equalizes educational opportunities at the macro-level. We also discuss whether similar mechanisms might exist in other educational systems.     

Estimating the number of clusters in a data set via the gap statistic

We propose a method (the 'gap statistic') for estimating the number of clusters (groups) in a set of data. The technique uses the output of any clustering algorithm (e.g. K -means or hierarchical), comparing the change in within-cluster dispersion with that expected under an appropriate reference null distribution. Some theory is developed for the proposal and a simulation study shows that the gap statistic usually outperforms other methods that have been proposed in the literature.     

Sektion Wissenssoziologie

Ohne Zusammenfassung     

德国关于电子电气设备的闭环供应链研究:一种生态效益计算方法

近来关于闭环供应链网络的文献中提出了两个重要问题:(1)如何制定平衡环境和经济效益的优化方案;(2)如何深刻理解二者间的效益背反关系。本文认为,针对环境和经济间的效益边界及其背反关系进行全面探索,可以有效解决环境保护和经济发展中的效益平衡问题。为了解决求解效益边界的多变量问题,本文设计了一个针对目标函数中的数值进行指数计算的生态效益算法,并在德国电子电气设备闭环供应链设计中进行了实证研究。