Representations for homomorphisms

Five different solutions to the problem of finding empirical meanings for the algebraically useful technique of homomorphisms in blockmodeling are described. They are the Lorrain-White, Pattison, Wu, modified Wu, and Bonacich approaches. All of them are designed to give meaning to a homomorphism in terms of characteristics of the relational matrices producing a semigroup, but they emphasize different aspects of the data. The Lorrain-White approach assumes that sets of relations are alternative expressions of an “underlying” relation. The Pattison and Bonacich approaches assume an underlying “clique” structure of structurally equivalent individuals. The Wu approaches assume that there is an “elite” set of individuals whose relational patterns define the homomorphism.     

Interval estimates for variance components

The fiducial approach to the two components of variance random effects model developed by Venables and James (1978) is related to the Bayesian approach of Box and Tiao (1973). The operating characteristics, under repeated sampling, of the resulting interval estimators for the “within classes” variance component are investigated, and the behaviour of the two sets of intervals is found to be very similar, the coverage frequency of 95% probability intervals being approximately 91% when the “between classes” variance component is zero but rising rapidly to 95% as the between component increases. The probability intervals are shown to be shorter on average than a comparable confidence interval based upon the within classes sum of squares, and to be robust against nonnormality in the class means.     

Two issues in the evaluation of job-shop schedules

Two issues are examined concerning the evaluation of job-shop schedules. First, machine and labor cost/utilization are suggested as alternatives to physical utilization criteria. Secondly, an exploration is made of the use of Kiviat Charts as a means of integrating multidimensional criteria for the overall evaluation of the quality of job shop schedules.     

Program evaluation in rehabilitation

Increased accountability and more encompassing accreditation standards have heightened interest in the role that evaluation research plays in improving the quality of life and independence for people with disabilities. The field of Program Evaluation is a valuable resource for conducting studies that meet the standards and information needs in the field of rehabilitation. This article describes the nature of evaluation research and illustrates its contribution to contemporary rehabilitation practice.     

Religion and Migration around the Globe: Introducing the Global Religion and Migration Database

International migration is a global phenomenon involving nearly 215 million people, equivalent to 3% of the world’s population. Previous databases of global migration catalog international migration using a variety of variables (sex, education, age); however, religion is rarely addressed within these data sets. Representing nearly half a million data points, the Global Religion and Migration Database (GRMD) was constructed – the only global database estimating the global migrant population (stock) by origin, destination, and religious affiliation. This research note serves as an introduction to the GRMD, detailing the construction of the database and providing key findings from a global perspective.     

‘IF I FEEL LIKE THIS,HOW DOES THE CHILD FEEL?’ CHILD PROTECTION WORKERS,SUPERVISION, MANAGEMENT AND ORGANISATIONAL RESPONSES TO PARENTAL VIOLENCE

This study analysed workers’ experiences of supervision following interactions with hostile and intimidating parents. This analysis examined management and organisational responses to worker stress, and assessed the adequacy of support that workers received. An online survey was designed to collect data on workers’ experiences and free text responses were qualitatively analysed for references to the supervision they received in response to working with parents. 590 participants responded to the survey. 402 were qualified social workers, and 423 worked in child protection. Participants had experienced a range of violent behaviour from parents. The overwhelming theme in responses was the lack of support and supervision workers received, often in stressful and frightening circumstances. Approximately one quarter of participants only used organisational procedures, guidelines or protocols on dealing with hostile parents. Workers reported that mismanaged parental hostility affected their practice and the quality of protection that children received. The violence experienced had a significant negative impact on their personal and professional lives. Organisational responses in the form of supervision and education were often inadequate and resulted in children receiving reduced quality of protection. Recommendations for policy and practice change are discussed, with the aim of caring for workers and the children they protect.     

Semiparametric methods for response-selective and missing data problems in regression

Suppose that data are generated according to the model f ( y | x ; θ ) g ( x ), where y is a response and x are covariates. We derive and compare semiparametric likelihood and pseudolikelihood methods for estimating θ for situations in which units generated are not fully observed and in which it is impossible or undesirable to model the covariate distribution. The probability that a unit is fully observed may depend on y , and there may be a subset of covariates which is observed only for a subsample of individuals. Our key assumptions are that the probability that a unit has missing data depends only on which of a finite number of strata that ( y , x ) belongs to and that the stratum membership is observed for every unit. Applications include case–control studies in epidemiology, field reliability studies and broad classes of missing data and measurement error problems. Our results make fully efficient estimation of θ feasible, and they generalize and provide insight into a variety of methods that have been proposed for specific problems.     

Permanency Planning: New Name for an Old Concept

In this article the author examines the concept of permanency planning, and the development of that concept in child welfare practice in Australia and overseas. The Paper examines the philosophical and ethical dilemmas associated with the concept, given the often-competing rights of parent and child.