The failure of meta-analytic asymptotics for the seemingly efficient estimator of the common risk difference

We consider the case of a multicenter trial in which the center specific sample sizes are potentially small. Under homogeneity, the conventional procedure is to pool information using a weighted estimator where the weights used are inverse estimated center-specific variances. Whereas this procedure is efficient for conventional asymptotics (e. g. center-specific sample sizes become large, number of center fixed), it is commonly believed that the efficiency of this estimator holds true also for meta-analytic asymptotics (e.g. center-specific sample size bounded, potentially small, and number of centers large). In this contribution we demonstrate that this estimator fails to be efficient. In fact, it shows a persistent bias with increasing number of centers showing that it isnot meta-consistent. In addition, we show that the Cochran and Mantel-Haenszel weighted estimators are meta-consistent and, in more generality, provide conditions on the weights such that the associated weighted estimator is meta-consistent.     

Population policies in advanced societies: Pronatalist and migration strategies

This paper discusses pronatalist and migration policies that have been introduced in selected European countries. Measures and objectives are briefly described before an evaluation of the efficacy of each is provided. The case studies chosen show that pronatalist policies have had limited effects. Migration policies seem to have been more effective, although their aims so far have been largely non-demographic. Migration strategies will increasingly have to be considered for demographic reasons in the future, to counterbalance population decline. Both pronatalist and migration strategies tend to conflict with other policies (social and economic policies, emancipation or housing policies), and to be in competition with the demands of an ageing society. Limits to the development or expansion of either strategy are spelled out. Finally a few untried mechanisms are mentioned.     

EXPLORA:content interpretation of data

Most approaches to applying knowledge-based techniques for data analyses concentrate on the context-independent statistical support. EXPLORA however is developed for the subject-specific interpretation with regard to the contents of the data to be analyzed (i.e. content interpretation). Therefore its knowledge base includes also the objects and semantic relations of the real system that produces the data. In this paper we describe the functional model representing the process of content interpretation, summarize the software architecture of the system and give some examples of its applications by pilot-users in survey analysis. EXPLORA addresses applications with data produced regularly which have to be analyzed in a routine way. The system systematically searches for statistical results (facts) to detect relations which possibly could be overlooked by a human analyst. On the other hand EXPLORA will help overcome the large bulk of information which today is usually still produced when presenting the data. Therefore a second knowledge process of content interpretation consists in discovering messages about the data by condensing the facts. Approaches for inductive generalization which have been developed for machine learning are utilized to identify common values of attributes of the objects to which the facts relate. At a later stage the system searches for interesting facts by applying redundancy rules and domaindependent selection rules. EXPLORA formulates the messages in terms of the domain, groups and orders them and even provides flexible navigations in the fact spaces.     

Das Karriereplateau

The career-plateau as challenge to enterprises, employees and consultantsThe authors intend to link life-span-psychology to career-research in order to make understand the phenomenon of career-plateau and how individuals and organisations can deal with it. People take stock in the middle of their lives and assess their personal or professional targets. This process often relates to a personal crisis, especially when the success rate of a job is an important part of the self-concept and hierarchical development has stopped simultaneously. Nevertheless, the desire for a career continues to exist. On top of that what makes it even harder is that the individual has to work at least 20 more years because of demographic reasons. We assume that the way how to manage this crisis has a big influence on performance motivation and that life-span-orientated management development can help the individual to overcome the crisis or even prevent it.