Neighborhood context and racial differences in early adolescent sexual activity

Evidence suggests that African American youths initiate sexual activity at earlier ages than do European American or Latino youths. Using data from a multilevel study in Chicago, we developed and tested a neighborhood-based model of the timing of first adolescent intercourse that emphasizes the impact of neighborhood structural disadvantage and collective efficacy on early sexual activity (at ages 11 to 16). In turn, we explored the extent to which neighborhood factors account for racial differences in the timing of first intercourse. The findings indicate that demographic background, family processes, peer influences, and developmental risk factors account for about 30% of the baseline increased likelihood of early sexual onset for African American youths compared with European American youths. However, a significant residual racial difference remained even after we considered a host of micro-level factors. Neighborhood-level concentrated poverty largely explained this residual racial difference. Collective efficacy also independently contributed to the delay of sexual onset. No significant baseline difference in age of sexual initiation was found between Latino and European American youths.     

Effect of family structure on life satisfaction: australian evidence

How do family arrangements affect subjective well-being? We investigate this issue using data pooled from the IsssA and HILDA, both large, representative national samples of Australia (pooled n=38 447). Our regression analysis of cross-sectional and panel data examines how large are the differences in life satisfaction according to marital status and cohabitation. We find that women and men in formal marriages experience higher levels of life satisfaction than do people in other family arrangements. Moreover, both multiple tests in the cross-section, and tests controlling for prior happiness in the panel analysis, suggest that this is a causal relationship. Aggregating up the levels of life satisfaction generated by different marriage and cohabitation arrangements across a lifetime, suggests that a life-long marriage is the most satisfying. Early divorce followed by an enduring second marriage is little worse (because little time is spent outside the married state). But divorce without remarriage, or long lasting cohabitation without formal marriage, reduce the lifetime sum of subjective well-being by 4–12% for both women and men.     

Auf dem Weg an die Spitze Anforderungen an Bewerber für Top-Positionen

En route to the top. Requirements on candidates for top positionsThe assessment of candidates for positions as managing director or as an executive committee member by means of management diagnostics has been frowned upon by German companies for a long time. There has, however, been a clear change of opinion regarding this matter in the meantime. The authors have developed a model of requirements to assess the competencies and potential critical for success. Six areas of responsibility are differentiated between thereby: “Ability to cope with complexity” and “development of decidedness”, “Will to create” and “establishment of structures”, “Establishment of bonds” and “ability of self-management”, and are divided into three levels: the personal level, the co-operative level and the level of corporate culture respectively.     

Inequality and welfare evaluation of heterogeneous income distributions

This paper establishes the principles that should govern the welfare and inequality analysis of heterogeneous income distributions. Two basic criteria – the equity preference condition and the compensation principle – are shown to be fundamentally incompatible. The paper favours the latter, thereby vindicating the traditional method of dealing with heterogeneous samples. However, inequality and welfare comparisons will usually be well defined only if equivalent incomes are obtained using constant scale factors; and researchers will need to distinguish clearly between inequality of nominal incomes and inequality of living standards. Furthermore, household observations must always be weighted according to family size.     

A weighted polynomial regression method for local fitting of spatial data

Typically, parametric approaches to spatial problems require restrictive assumptions. On the other hand, in a wide variety of practical situations nonparametric bivariate smoothing techniques has been shown to be successfully employable for estimating small or large scale regularity factors, or even the signal content of spatial data taken as a whole.We propose a weighted local polynomial regression smoother suitable for fitting of spatial data. To account for spatial variability, we both insert a spatial contiguity index in the standard formulation, and construct a spatial-adaptive bandwidth selection rule. Our bandwidth selector depends on the Gearys local indicator of spatial association. As illustrative example, we provide a brief Monte Carlo study case on equally spaced data, the performances of our smoother and the standard polynomial regression procedure are compared.This note, though it is the result of a close collaboration, was specifically elaborated as follows: paragraphs 1 and 2 by T. Sclocco and the remainder by M. Di Marzio. The authors are grateful to the referees for constructive comments and suggestions.     

Economic potential and entry into marriage and cohabitation

This article explores the relationship between economic potential and rates of entry into marriage and cohabitation. Using data from the 1990 census and the 1980-1992 High School and Beyond (Sophomore Cohort), we developed a method for explicitly estimating five time-varying measures of earnings potential. The analyses of union formation are based on an intergenerational panel study of parents and children, to which our measures of earnings potential were appended. The results indicate that all five measures of earnings potential strongly and positively influence the likelihood of marriage for men, but not for women. Earnings potential does not affect entry into cohabiting unions for either men or women.     

An evaluation of population projections by age

A number of studies have evaluated the accuracy of projections of the size of the total population, but few have considered the accuracy of projections by age group. For many purposes, however, the relevant variable is the population of a particular age group, rather than the population as a whole. We investigated the precision and bias of a variety of age-group projections at the national and state levels in the United States and for counties in Florida. We also compared the accuracy of state and county projections that were derived from full-blown applications of the cohort-component method with the accuracy of projections that were derived from a simpler, less data-intensive version of the method. We found that age-group error patterns are different for national projections than for subnational projections; that errors are substantially larger for some age groups than for others; that differences in errors among age groups decline as the projection horizon becomes longer; and that differences in methodological complexity have no consistent impact on the precision and bias of age-group projections.     

Missing at random (MAR) in nonparametric regression - A simulation experiment

The additive model is considered when some observations on x are missing at random but corresponding observations on y are available. Especially for this model, missing at random is an interesting case because the complete case analysis is expected to be no more suitable. A simulation experiment is reported and the different methods are compared based on their superiority with respect to the sample mean squared error. Some focus is also given on the sample variance and the estimated bias. In detail, the complete case analysis, a kind of stochastic mean imputation, a single imputation and the nearest neighbor imputation are discussed.     

Editorial

Ohne Zusammenfassung

---

Editorial

     

The densest <Emphasis Type="Italic">k</Emphasis>-subgraph problem on clique graphs

The Densest k-Subgraph (DkS) problem asks for a k-vertex subgraph of a given graph with the maximum number of edges. The problem is strongly NP-hard, as a generalization of the well known Clique problem and we also know that it does not admit a Polynomial Time Approximation Scheme (PTAS). In this paper we focus on special cases of the problem, with respect to the class of the input graph. Especially, towards the elucidation of the open questions concerning the complexity of the problem for interval graphs as well as its approximability for chordal graphs, we consider graphs having special clique graphs. We present a PTAS for stars of cliques and a dynamic programming algorithm for trees of cliques. M.L. is co-financed within Op. Education by the ESF (European Social Fund) and National Resources. V.Z. is partially supported by the Special Research Grants Account of the University of Athens under Grant 70/4/5821.