Aktuelle Herausforderungen im internen Change Management der Commerzbank und der Deutschen Bahn

Gruppe. Interaktion. Organisation. Zeitschrift für Angewandte Organisationspsychologie (GIO) - Dieser Artikel der Zeitschrift ?Gruppe. Interaktion. Organisation. (GIO)“...     

On Ehrhart polynomials and probability calculations in voting theory

In voting theory, analyzing the frequency of an event (e.g. a voting paradox), under some specific but widely used assumptions, is equivalent to computing the exact number of integer solutions in a system of linear constraints. Recently, some algorithms for computing this number have been proposed in social choice literature by Huang and Chua (Soc Choice Welfare 17:143–155 2000) and by Gehrlein (Soc Choice Welfare 19:503–512 2002; Rev Econ Des 9:317–336 2006). The purpose of this paper is threefold. Firstly, we want to do justice to Eugène Ehrhart, who, more than forty years ago, discovered the theoretical foundations of the above mentioned algorithms. Secondly, we present some efficient algorithms that have been recently developed by computer scientists, independently from voting theorists. Thirdly, we illustrate the use of these algorithms by providing some original results in voting theory. Helpful comments by Philippe Clauss and his team are gratefully acknowledged.     

Minimum aberration and model robustness for two-level fractional factorial designs

The performance of minimum aberration two-level fractional factorial designs is studied under two criteria of model robustness. Simple sufficient conditions for a design to dominate another design with respect to each of these two criteria are derived. It is also shown that a minimum aberration design of resolution III or higher maximizes the number of two-factor interactions which are not aliases of main effects and, subject to that condition, minimizes the sum of squares of the sizes of alias sets of two-factor interactions. This roughly says that minimum aberration designs tend to make the sizes of the alias sets very uniform. It follows that minimum aberration is a good surrogate for the two criteria of model robustness that are studied here. Examples are given to show that minimum aberration designs are indeed highly efficient.     

Multiple pathways to adulthood: expanding the learning options for urban youth

Some learning environments show particular promise of creating pathways to postsecondary education, careers, and engaged citizenship for urban young adults from ages fifteen to twenty-four.     

Characteristics of Gambling Helpline Callers with Self-Reported Gambling and Alcohol Use Problems

The characteristics of problem gamblers calling the Connecticut Council on Problem Gambling (CCPG) gambling helpline during the years 2000–2001 (n = 960) were examined based on the presence or absence of self-reported alcohol use problems. A relatively low proportion of callers reported a problem with alcohol use (173/960 or 18.0%), and of those acknowledging an alcohol use problem, the majority reported a past rather than current problem (143/173 or 82.7%). A logistic regression analysis found that, as compared with problem gamblers denying any alcohol use problems, those reporting past or current alcohol use problems were more likely to be male and more frequently acknowledged problems with more forms of gambling, suicide attempts related to gambling, arrests secondary to gambling, daily tobacco use, drug use problems, prior substance abuse treatment, and family histories positive for alcohol and drug use problems. The findings highlight the strong relationship between alcohol use problems and other substance use problems, and suggest that problem gamblers with as compared with those without alcohol use problems demonstrate greater problems in multiple areas (arrest, attempted suicide) linked by impaired impulse control.Please address correspondence to Marc N. Potenza, Director, Problem Gambling Clinic; Director, Women and Addictive Disorders Core, Women’s Health Research at Yale; Yale University School of Medicine, Connecticut Mental Health Center, Room S-104, 34 Park Street, New Haven, CT 06519. E-mail: marc.potenza@yale.edu.     

We Know Some Things: Parent–Adolescent Relationships in Retrospect and Prospect

This article examines the most important ideas to have emerged from the last 25 years of research on adolescent development in the family context and suggests some directions for the future. Two major sets of questions organize the review. First, how can we best characterize normative family relationships during adolescence, and, more specifically, is adolescence a time of parent à child conflict? Second, how do variations in parent – child relationships affect the developing adolescent? The answer to the first question depends on what is meant by conflict and, more importantly, from whom one gathers data. There is a need for a new perspective on the family, one that emphasizes the different viewpoints and stakes that parents and adolescents bring to their relationship with each other. Special attention should be paid to studies of the mental health of parents of adolescents. With regard to the second question, it is argued that there is enough evidence to conclude that adolescents benefit from having parents who are authoritative: warm, firm, and accepting of their needs for psychological autonomy. Therefore, it would seem most beneficial to institute a systematic, large‐scale, multifaceted, and ongoing public health campaign to educate parents about adolescence, one that draws on the collective resources and expertise of health‐care professionals, scientists, governmental agencies, community organizations, schools, religious institutions, and the mass media.     

Empirical Bayes estimates of finite mixture of negative binomial regression models and its application to highway safety

The empirical Bayes (EB) method is commonly used by transportation safety analysts for conducting different types of safety analyses, such as before–after studies and hotspot analyses. To date, most implementations of the EB method have been applied using a negative binomial (NB) model, as it can easily accommodate the overdispersion commonly observed in crash data. Recent studies have shown that a generalized finite mixture of NB models with K mixture components (GFMNB-K) can also be used to model crash data subjected to overdispersion and generally offers better statistical performance than the traditional NB model. So far, nobody has developed how the EB method could be used with finite mixtures of NB models. The main objective of this study is therefore to use a GFMNB-K model in the calculation of EB estimates. Specifically, GFMNB-K models with varying weight parameters are developed to analyze crash data from Indiana and Texas. The main finding shows that the rankings produced by the NB and GFMNB-2 models for hotspot identification are often quite different, and this was especially noticeable with the Texas dataset. Finally, a simulation study designed to examine which model formulation can better identify the hotspot is recommended as our future research.     

The Effect of Imputation Procedures on First Birth Intervals: Evidence from Five African Fertility Surveys

In most African societies there is little motivation to remember dates of demographic events with the level of precision required in demographic surveys. Consequently it is common that the large majority of survey respondents can provide only the calendar year of occurrence or their age at the time of the event. The World Fertility Survey Group decided to handle the problem of poor date reporting by using a computer program to impute the missing information. This article illustrates the effect of these imputation procedures on cross-national differentials in the proportion of premarital first births in Benin, Cameroon, Cote d’Ivoire, Ghana, and Nigeria. The analysis demonstrates that the exceptionally low proportion of premarital first births in Ghana is an artifact of the imputation procedures.     

Preparing adolescents for adulthood

Pregnancy-related school dropouts have become a matter of public concern throughout sub-Saharan Africa. In most cases, schoolgirls who become pregnant either have to resort to unsafe illegal abortions, or they face official school expulsion. Because girls who drop out of school due to pregnancy usually do not return to school to complete their education after the birth of their child, their opportunities for socioeconomic advancement are limited. Many African governments have included family life education programs in the school curriculum in an attempt to educate adolescents about the consequences and responsibilities associated with sexual activity. The high rates of schoolgirl pregnancies suggest that these programs have their shortcomings, and indicate that educational policies should attempt not only to reduce the incidence of schoolgirl pregnancies, but also to assist pregnant schoolgirls to complete their education. In this paper, we use data from a sample of 154 Kenyan primary and secondary schools to study differentials in the extent to which various types of schools are affected by pregnancy-related school dropouts, and to examine the opinions of the head teachers regarding teaching about contraceptive methods and readmittance of pregnancy-related dropouts.