Estimation of the Intraclass Correlation Coefficient for the Analysis of Covariance Model

For the unbalanced analysis of covariance model with one covariate, a simple formula is given for the intraclass correlation coefficient estimator that results from Henderson's Method 3 estimation of variance components. Example calculations and the corresponding interpretations are given for a study of the correlation of iron content among brothers. The example illustrates the manner in which the estimator depends on the pattern of correlation between the covariate and the variable under investigation.     

Ecological Bias: Use of Maximum-Entropy Approximations

The focus of geographical studies in epidemiology has recently moved towards looking for effects of exposures based on data taken at local levels of aggregation (i.e. small areas). This paper investigates how regression coefficients measuring covariate effects at the point level are modified under aggregation. Changing the level of aggregation can lead to completely different conclusions about exposure–effect relationships, a phenomenon often referred to as ecological bias. With partial knowledge of the within‐area distribution of the exposure variable, the notion of maximum entropy can be used to approximate that part of the distribution that is unknown. From the approximation, an expression for the ecological bias is obtained; simulations and an example show that the maximum‐entropy approximation is often better than other commonly used approximations.     

RELAXING ASSUMPTIONS IN THE ONE SAMPLE t-TEST

This paper reviews what is currently known about the behaviour of the t-statistic when one is no longer sampling from a normal distribution. Suppose Y is a batch of data on which the t-test is performed. Briefly then, heavy-tailed components of Y give a light-tailed t , positive correlation among Y gives a heavy-tailed t, and positively skewed components of Y give a negatively skewed t. The emphasis is on understanding why one gets this type of behaviour, although some numerical tables are presented to illustrate the conclusions.     

A few statistical principles for data science

In any other circumstance, it might make sense to define the extent of the terrain (Data Science) first, and then locate and describe the landmarks (Principles). But this data revolution we are experiencing defies a cadastral survey. Areas are continually being annexed into Data Science. For example, biometrics was traditionally statistics for agriculture in all its forms but now, in Data Science, it means the study of characteristics that can be used to identify an individual. Examples of non-intrusive measurements include height, weight, fingerprints, retina scan, voice, photograph/video (facial landmarks and facial expressions) and gait. A multivariate analysis of such data would be a complex project for a statistician, but a software engineer might appear to have no trouble with it at all. In any applied-statistics project, the statistician worries about uncertainty and quantifies it by modelling data as realisations generated from a probability space. Another approach to uncertainty quantification is to find similar data sets, and then use the variability of results between these data sets to capture the uncertainty. Both approaches allow ‘error bars’ to be put on estimates obtained from the original data set, although the interpretations are different. A third approach, that concentrates on giving a single answer and gives up on uncertainty quantification, could be considered as Data Engineering, although it has staked a claim in the Data Science terrain. This article presents a few (actually nine) statistical principles for data scientists that have helped me, and continue to help me, when I work on complex interdisciplinary projects.     

Conversion Ratios, Efficiency and Obfuscation: A Study of the Impact of Changed UK Charity Accounting Requirements on External Stakeholders

Key stakeholders in the UK charity sector have, in recent years, advocated greater accountability for charity performance. Part of that debate has focussed on the use of conversion ratios as indicators of efficiency, with importance to stakeholders being contrasted with charities’ apparent reluctance to report such measures. Whilst, before 2005, conversion ratios could have been computed from financial statements, changes in the UK charity SORP have radically altered the ability of users to do this. This article explores the impact on the visibility of such information through an analysis of the financial statements of large UK charities before and after the 2005 changes. Overall, the findings suggest that, despite the stated intention of increasing transparency in respect of charity costs, the application of the changes has resulted in charities ‘managing’ the numbers and limiting their disclosures, possibly to the detriment of external stakeholders.     

Breaking the in‐group out‐group: shifting boundaries in transnational partner choice processes of individuals of Moroccan,Tunisian, Algerian,Turkish, Punjabi Sikh,Pakistani and Albanian descent in Belgium

The ongoing popularity in some second and third generation migrants in Western Europe of marrying a partner from the countries of origin of their (grand)parents is considered to be problematic for micro and macro level societal integration of some migrant populations. Partner choice and marriage practices in migrant communities are problematized in public, media and political discourses by discriminating them from marriage practices in the ‘native’ population on the basis of three related dichotomies: (1) agency versus structure, (2) us versus them and (3) romantic versus instrumental marriage intentions dichotomies. By means of in‐depth qualitative research methodologies on the partner choice processes of women and men of Turkish, Moroccan, Algerian, Tunisian, Punjabi Sikh, Pakistani and Albanian descent in Belgium and an intersectional theoretical approach, this article aims to deconstruct popular and simplifying dichotomous representations of partner choice processes in these migrant populations. Our study reveals how religious, gender and social class boundaries are stretched to meet personal/individual desires and preferences. Individuals do experience social restrictions when it concerns social group boundaries and the potential partners that they can look for. At the same time individuals are never fully determined by their social environment, they creatively develop strategies to by‐pass certain restrictions and to some extent are able to meet their personal needs while being sensitive to the desires of their social environment.     

Regimes of Mobility Across the Globe

Mobility studies emerged from a postmodern moment in which global ‘flows’ of capital, people and objects were increasingly noted and celebrated. Within this new scholarship, categories of migrancy are all seen through the same analytical lens. This article and Regimes of Mobility: Imaginaries and Relationalities of Power, the special issue of JEMS it introduces, build on, as well as critique, past and present studies of mobility. In so doing, this issue challenges conceptual orientations built on binaries of difference that have impeded analyses of the interrelationship between mobility and stasis. These include methodological nationalism, which counterpoises concepts of internal and international movement and native and foreigner, and consequently normalises stasis. Instead, the issue offers a regimes of mobility framework that addresses the relationships between mobility and immobility, localisation and transnational connection, experiences and imaginaries of migration, and rootedness and cosmopolitan openness. The introduction highlights how, within this framework and its emphasis on social fields of differential power, the contributors to this collection ethnographically explore the disparities, inequalities, racialised representations and national mythscapes that facilitate and legitimate differential mobility and fixity. Although the authors examine nation-state building processes, their analysis is not confined by national boundaries.     

Situation and Social Network in Cities*

Un problème significatif dans l'élaboration et l'utilisation de réseaux sociaux en recherche urbaine se rapporte à la spécification du contenu des relations de réseau. Dans une étude sur le terrain chez les Danois américains de la Californie, certains facteurs furent de grande utilité dans la définition des liens de réseau. Ce sont: le cadre institutionnel à l'intérieur duquel s'élaborent les liens de réseau; les situations qui leur permettent d'être opérants et la nature affective de ces liens de réseau. En plus de leur valeur opératoire, ces facteurs permettent au chercheur d'évaluer la qualité et la diversité de la vie urbaine. A significant problem in the construction and use of social networks in urban research is that of specifying the content of network relationships. In fieldwork among Danish-Americans in California, the institutional framework in which network ties were recruited, the situations in which such ties were activated, and the affective nature of network links were useful in defining network bonds. In addition to their operational utility, these factors allow the investigator to assess the quality and diversity of urban life.     

Assessing Service Level Targets in Production and Inventory Planning*

In production and stock planning, the relationship between customer service, defined as the ability to meet demand for finished goods from in-stock inventory, and expected profits or expected costs can be represented by a simple reliability curve. The shape of this curve depends upon the parameters of the demand process, specifically the expected level of demand, standard deviation and correlation structure, as well as upon the capacities and initial state of the production and inventory system. A model is presented which explicitly determines this trade-off curve for a firm. The model is intended both as an operational model to aid managers in setting revenue and service targets which are compatible with the capacities and resources of the firm, and as a tool for exploring relationships between the parameters of the demand process and the constraints of the physical production and inventory system. The results illustrate that the level of risk depends strongly on the variability of the demand process, the cost structure, the capacities and initial state of the system and, to a lesser extent, the correlation in demand between succeeding periods. Results suggest that establishing service level targets consistent with the firm's strategic orientation must be done in consideration of both the characteristics of the demand process and the capacities of the production and inventory system. The model provides a tool for estimating the premium above unit cost which must be paid to provide a designated service level.     

Patterns of Social Support in the Middle Childhood to Early Adolescent Transition: Implications for Adjustment

Children's social networks often include close family members, extended family members, and friends, but little is known about interindividual differences in the patterning of support from these sources. In this study, we used person‐oriented analyses to differentiate patterns of support for children undergoing the transition to adolescence. Social network and adjustment data were collected for an ethnically diverse sample of 691 fourth‐ and sixth‐grade children, with a two‐year follow‐up. Cluster analyses identified one pattern of support from both close family members and friends, a second pattern of support from both close and extended family members, and a third pattern of support primarily from close family members alone. Participants receiving support from close family in combination with either extended family or friends were better adjusted than were those without multiple support resources. The results suggest that a meaningful typology of children's social networks can be developed.