ESTIMATING A RATIO OF MEANS FROM BIVARIATE COUNTS WITH APPLICATIONS IN STEREOLOGY

In survey sampling and in stereology, it is often desirable to estimate the ratio of means θ= E(Y)/E(X) from bivariate count data (X, Y) with unknown joint distribution. We review methods that are available for this problem, with particular reference to stereological applications. We also develop new methods based on explicit statistical models for the data, and associated model diagnostics. The methods are tested on a stereological dataset. For point‐count data, binomial regression and bivariate binomial models are generally adequate. Intercept‐count data are often overdispersed relative to Poisson regression models, but adequately fitted by negative binomial regression.     

Fast computation of spatially adaptive kernel estimates

Kernel smoothing of spatial point data can often be improved using an adaptive, spatially varying bandwidth instead of a fixed bandwidth. However, computation with a varying bandwidth is much more demanding, especially when edge correction and bandwidth selection are involved. This paper proposes several new computational methods for adaptive kernel estimation from spatial point pattern data. A key idea is that a variable-bandwidth kernel estimator for d-dimensional spatial data can be represented as a slice of a fixed-bandwidth kernel estimator in \((d+1)\)-dimensional scale space, enabling fast computation using Fourier transforms. Edge correction factors have a similar representation. Different values of global bandwidth correspond to different slices of the scale space, so that bandwidth selection is greatly accelerated. Potential applications include estimation of multivariate probability density and spatial or spatiotemporal point process intensity, relative risk, and regression functions. The new methods perform well in simulations and in two real applications concerning the spatial epidemiology of primary biliary cirrhosis and the alarm calls of capuchin monkeys.     

Marital Satisfaction,Family Emotional Expressiveness,Home Learning Environments,and Children's Emergent Literacy

The current study investigates associations among marital satisfaction, family emotional expressiveness, the home learning environment, and preschool‐aged children's emergent literacy skills among 385 Midwestern mothers and their children. Path analyses examined how marital satisfaction related to emotional expressiveness in the home and whether this path was associated with the home learning environment and children's literacy skills. Higher maternal satisfaction was associated with higher levels of positive and lower levels of negative family emotional expressiveness. Additionally, family emotional environments characterized by mothers with higher positive expression were related to better home learning environments, which in turn were associated with higher literacy skills in children. Study findings underscore the importance of marital and family processes when considering young children's academic development.     

Student Views on Good Practice in Social Work Education

This article focuses on the delivery of a social work degree programme in England, one of the constituent jurisdictions of the United Kingdom, and explores student perceptions of their learning experience and what constitutes effective teaching. The data are drawn from a larger research project which is ongoing and focuses upon the specific ways in which the BSc Hons Social Work degree at a university in the East Midlands prepares students to meet the demands of employers. Linked to the national evaluation of the new social work degree, social work academics at the university worked with final year social work degree students as co-researchers to evaluate student views on the quality of teaching practices across the teaching team.     

‘Opportunity led work’: 1. The concept

This paper introduces the concept of ‘opportunity led work’: the creative use of challenges and opportunities for communication which arise in everyday practice, especially in group care. The paper sets the concept in context by defining and illustrating the area of work in question, by reviewing the relevant literature, by briefly outlining the framework and then locating it alongside other perspectives on group care practice. There is also some consideration of the practical implication of applying this framework both in practice and in the training context. There is an emphasis in the illustrative material on the use of this concept in residential child care.     

Defining Problems Fast and Slow: The U‐shaped Effect of Problem Definition Time on Project Duration

This study examines how time spent in problem definition affects problem solving in projects such as Six Sigma projects. Our hypotheses are tested using data collected from 1558 Six Sigma projects in a company. The results show evidence of a U‐shaped relationship between the amount of time spent in the Define phase and project duration. This finding suggests that spending too little time on problem definition potentially causes poor problem formulation, which leads to deficient problem solving and lengthens overall project time. On the other hand, too much time spent on problem definition can lead to unneeded delays in project completion due to diminishing returns on problem definition efforts. Furthermore, the optimal balance between spending too little and too much time depends on prior project experience and project complexity. Prior project experience reduced project completion time and weakened the U‐shaped effect. Conversely, complex projects took longer and appeared to show some evidence of a stronger U‐shaped effect; this suggests balancing the time spent in the Define phase was more challenging for complex projects. Our study also underscores the importance of managing project duration, as projects that were completed faster tended to be associated with higher project savings.     

Cairo and the changing definition of population and development issues

The goal of the United Nations International Conference on Population and Development (ICPD), held in Cairo in September 1994, was to agree on a Programme of Action in the field of population and development which would supersede the Plan of Action agreed to at Bucharest in 1974 and subsequently amended ten years later in Mexico City. The main purpose of the present paper is to characterize some of the principal intellectual and ideological developments of the last 20 years which have had an impact on the definition of this goal. I conclude with some brief comments on the Programme of Action adopted by consensus at the Conference. This is an amended version of the paper I presented at the Seventh National Conference of the Australian Population Association (in a Plenary Session entitled ‘Messages from Cairo’), held in Canberra in September 1994.