An application of cartographic area interpolation to German administrative data

In many situations the applied researcher wishes to combine different data sources without knowing the exact link and merging rule. This paper considers different cartographic interpolation methods for interpolating attributes from German employment office districts to German counties and vice versa. In particular, we apply dasymetric weighting as an alternative to simple area weighting, both of which are based on estimated intersection areas. We also present conditions under which the choice of interpolation method does not matter and confirm the theoretical results with a simulation study. Our application to German administrative data suggests robustness of estimation results of interpolated attributes with respect to the choice of interpolation method. We provide weighting matrices for regional data sources of the two largest German data producers.     

Comparison of different estimation techniques for portfolio selection

The main problem in applying the mean-variance portfolio selection consists of the fact that the first two moments of the asset returns are unknown. In practice the optimal portfolio weights have to be estimated. This is usually done by replacing the moments by the classical unbiased sample estimators. We provide a comparison of the exact and the asymptotic distributions of the estimated portfolio weights as well as a sensitivity analysis to shifts in the moments of the asset returns. Furthermore we consider several types of shrinkage estimators for the moments. The corresponding estimators of the portfolio weights are compared with each other and with the portfolio weights based on the sample estimators of the moments. We show how the uncertainty about the portfolio weights can be introduced into the performance measurement of trading strategies. The methodology explains the bad out-of-sample performance of the classical Markowitz procedures.     

Statistical consulting

The paper and the special issue focus on the activity of statistical consulting and its varieties. This includes academic consulting, consulting to and in industry as well as statistics in public media.     

Generalized model for IGC growth in aluminum alloys

A generalized brick wall model is developed to describe intergranular corrosion in Equi-axed AA7178-T6 and Wingskin AA7178-T6 aluminum alloys. The intergranular corrosion rate is highly related to grain size and shape. High strength aluminum alloys are often elongated and anisotropic, with the fastest nominal IGC growth rate in the longitudinal direction (L) or long transverse direction (T) and the slowest in the short transverse direction (S). We propose a three-way intersection model and use it to simulate the corrosion kinetics for each direction. With a proper combination of model parameters, the generalized IGC model provides a good fit to experimental data developed by the foil penetration technique.     

Describing the Dynamics of Attention to TV Commercials: A Hierarchical Bayes Analysis of the Time to Zap an Ad

This paper provides insights into the dynamics of attention to TV commercials via an analysis of the length of time that commercials are viewed before being 'zapped'. The model, which incorporates a flexible baseline hazard rate and captures unobserved heterogeneity across both consumers and commercials using a hierarchical Bayes approach, is estimated on two datasets in which commercial viewing is captured by a passive online device that continually monitors a household's TV viewing. Consistent with previous findings in psychology about the nature of attentional engagement in TV viewing, baseline hazard rates are found to be non-monotonic. In addition, the data show considerable ad-to-ad and household-to-household heterogeneity in zapping behavior. While one of the datasets contains some information on characteristics of the ads, these data do not reveal any firm links between the ad heterogeneity and the ad characteristics. A number of methodological and computational issues arise in the hierarchical Bayes analysis.     

Multi-phase sampling under cost constraints

Multi-phase sampling (M-PhS) scheme is useful when the interest is in the estimation of the population mean of an expensive variable strictly connected with other cheaper (auxiliary) variables. The MSE is an accuracy measure of an estimator. Usually it decreases as the sample size increases. In practice the sample size cannot become arbitrarily large for possible cost constraints. From a practical point of view it would be useful to know the sample sizes which guarantee the best accuracy of the estimates for fixed costs. These “optimum” sample sizes can be, in some cases, computable but not admissible. In other cases, they can be neither admissible nor computable. The main goal of this paper is to propose a solution for both these situations. It will be clear that in both situations the solution is to consider a M-PhS scheme with one or more phases less.     

H-likelihood: problems and solutions

In recent issues of this journal it has been asserted in two papers that the use of h-likelihood is wrong, in the sense of giving unsatisfactory estimates of some parameters for binary data (Kuk and Cheng, 1999; Waddington and Thompson, 2004) or theoretically unsound (Kuk and Cheng, 1999). We wish to refute both these assertions.     

Nonconglomerative coherent conditional probabilities in statistical inference

Noteworthy connections among conglomerability, countable additivity and coherence are discussed in detail, reaching the conclusion that nonconglomerable conditional probabilities must not be doomed and play a significant role in statistical inference. Extended and updated version of a contributed paper presented at the International Conference on “Information Processing and Management of Uncertainty in knowledge-based systems”, IPMU 2004, Perugia, Italy.     

The dynamics of negation: identity formation among Palestinian Arab college students inside the green line

How does granting certificates of ‘business clean of Arab workers’ to owners of shops, stores, and Jewish businesses who prove they are not employing Arab workers shape identity? Identity development involves making sense of, and coming to terms with, the social world one inhabits, recognizing choices and making decisions within contexts, and finding a sense of unity within one's self while claiming a place in the world. Since there is no objective, ahistoric, universal trans-cultural identity, views of identity must be historically and culturally situated. This paper explores identity issues among members of the Palestinian Arab minority in Israel. While there is a body of literature exploring this subject, we will offer a different perspective by contextualizing the political and economic contexts that form an essential foundation for understanding identity formation among this minority group. We argue that, as a genre of settler colonialism, ‘pure settlement colonies’ involve the conquering not only of land, but of labor as well, excluding the natives from the economy. Such an exclusion from the economy is significant for its cultural, social, and ideological consequences, and therefore is especially significant in identity formation discussed in the paper. We briefly review existing approaches to the study of identity among Palestinian Arabs in Israel, and illustrate our theoretical contextual framework. Finally, we present and discuss findings from a new study of identity among Palestinian Arab college students in Israel through the lens of this framework.     

Can physicians lead other physicians into the future?

This article reflects upon some of the dynamics that prevent physicians from successfully engaging change. Physicians are enculturated to the competitive and hierarchical, and to value personal autonomy. These traits promote distrust and inhibit the formation of collaborative relationships. At this time of growing complexity, when most other industries are developing styles of work based on teamwork, worker empowerment, cross training, and information sharing, physicians cling to the metaphor of the ship's captain, a lone decision-marker and authoritarian possessor of grand knowledge. And yet, in order to lead, physicians need to learn to work differently and nurture a more collaborative approach. The author's blueprint for change includes: Stop trying to manage consensus; commit to measured accountability; think systemically; don't make the mistake of thinking that people will follow because you are right; and, most importantly, create relationships based on shared purpose and principles.