Klassenlage und Bildungsentscheidungen

This empirical study seeks to contribute to the explanation of class differences in educational opportunities in the transition from primary to secondary education. According to recent theoretical explanations the social inequality in education results — apart from the historical conditions and institutions of the educational system — from rational choices of parents about the continuation of their children’s education. There is a nexus between class specific evaluation of costs and benefits of higher education and educational choice, which depends on the parents’ resources and the selection and allocation function of the educational system. This interrelationship results in unequal educational attainment among the children of different social classes. These hypotheses are tested by employing a two-step model of the dynamics of choices and actual transition. Using panel data and logistic regression as well as considering the children’s social origin the rise of educational aspirations and the following transition to higher education tracks are analyzed. The results lend support to the mechanisms and processes assumed by the subjective expected utility approach. However, there is an open question about the historical persistence of class differences in education in spite of educational expansion and school reforms.     

Practical Maximum Pseudolikelihood for Spatial Point Patterns(with Discussion)

This paper describes a technique for computing approximate maximum pseudolikelihood estimates of the parameters of a spatial point process. The method is an extension of Berman & Turner's (1992) device for maximizing the likelihoods of inhomogeneous spatial Poisson processes. For a very wide class of spatial point process models the likelihood is intractable, while the pseudolikelihood is known explicitly, except for the computation of an integral over the sampling region. Approximation of this integral by a finite sum in a special way yields an approximate pseudolikelihood which is formally equivalent to the (weighted) likelihood of a loglinear model with Poisson responses. This can be maximized using standard statistical software for generalized linear or additive models, provided the conditional intensity of the process takes an 'exponential family' form. Using this approach a wide variety of spatial point process models of Gibbs type can be fitted rapidly, incorporating spatial trends, interaction between points, dependence on spatial covariates, and mark information.     

Estimating the propagation rate of a viral infection of potato plants via mixtures of regressions

A problem arising from the study of the spread of a viral infection among potato plants by aphids appears to involve a mixture of two linear regressions on a single predictor variable. The plant scientists studying the problem were particularly interested in obtaining a 95% confidence upper bound for the infection rate. We discuss briefly the procedure for fitting mixtures of regression models by means of maximum likelihood, effected via the EM algorithm. We give general expressions for the implementation of the M-step and then address the issue of conducting statistical inference in this context. A technique due to T. A. Louis may be used to estimate the covariance matrix of the parameter estimates by calculating the observed Fisher information matrix. We develop general expressions for the entries of this information matrix. Having the complete covariance matrix permits the calculation of confidence and prediction bands for the fitted model. We also investigate the testing of hypotheses concerning the number of components in the mixture via parametric and 'semiparametric' bootstrapping. Finally, we develop a method of producing diagnostic plots of the residuals from a mixture of linear regressions.     

An Economic Approach to Achievement and Improvement Indexes

This study proposes a usefulalternative to the ``aggregate deprivationindex' which is used to measure the well-beingsof individuals in different countries orgeographic locations. Furthermore, we alsopropose an improvement index which alleviateswell known difficulties associated withovertime comparisons of ``aggregate deprivationindex'. While deriving our indexes, we pursuedan economic approach to index numbers theoryand relied on the assumptions of optimizingbehavior. The proposed achievement index hasits roots in the theory of quantity indexeswhose axiomatic properties are wellestablished. The roots of our improvement indexon the other hand, is well grounded in theproductivity growth literature. The study alsoprovides a numerical example.     

Separator-based data reduction for signed graph balancing

Polynomial-time data reduction is a classical approach to hard graph problems. Typically, particular small subgraphs are replaced by smaller gadgets. We generalize this approach to handle any small subgraph that has a small separator connecting it to the rest of the graph. The problem we study is the NP-hard Balanced Subgraph problem, which asks for a 2-coloring of a graph that minimizes the inconsistencies with given edge labels. It has applications in social networks, systems biology, and integrated circuit design. The data reduction scheme unifies and generalizes a number of previously known data reductions, and can be applied to a large number of graph problems where a coloring or a subset of the vertices is sought. To solve the instances that remain after reduction, we use a fixed-parameter algorithm based on iterative compression with a very effective heuristic speedup. Our implementation can solve biological real-world instances exactly for which previously only approximations were known. In addition, we present experimental results for financial networks and random networks.     

Der Beitrag der Theorie subjektiver Werterwartung und anderer RC-Theorien zur Erklärung der herkunftsbedingten Bildungschancen und Bildungsungleichheit

In his critical appreciation of my article about the correlation of social class, educational choice and inequality of education Haller seeks to discuss critical aspects of the applied Rational Choice theories. It is delineated that his objections are based on theoretical, methodological and statistical misunderstandings.     

Entwickeln im Team – Effekte für den Einzelnen

This study tested the effects of a 2-day team building intervention on team members’ team identification, social support and collective self-efficacy. Members (n?=?32) of three teams from different sectors completed questionnaires before, directly after and six weeks after the team building intervention. Two teams served as control groups. Results showed lasting positive effects of team building on identification, support and collective self-efficacy in the training groups but no changes in the control groups.     

Conditional statistical inference and quantification of relevance

Summary. We argue that it can be fruitful to take a predictive view on notions such as the precision of a point estimator and the confidence of an interval estimator in frequentist inference. This predictive approach has implications for conditional inference, because it immediately allows a quantification of the concept of relevance for conditional inference. Conditioning on an ancillary statistic makes inference more relevant in this sense, provided that the ancillary is a precision index. Not all ancillary statistics satisfy this demand. We discuss the problem of choice between alternative ancillary statistics. The approach also has implications for the best choice of variance estimator, taking account of correlations with the squared error of estimation itself. The theory is illustrated by numerous examples, many of which are classical.     

Nightingales Schwestern

The paper discusses the gendering process in hospitals: Doctors cure, nurses attend. Even though both occupations have the same importance, curing, the male domain, is the most powerful one. Therefore conflicts exist between nurses and doctors. These conflicts make cooperation difficult. Many of them are determined by unconscious fantasies about sex roles: what real men and real women should be. Making the medical care more professional presupposes a fair-minded confrontation between these fantasies.