Optimal adaptive sequential designs for crossover bioequivalence studies

In prior works, this group demonstrated the feasibility of valid adaptive sequential designs for crossover bioequivalence studies. In this paper, we extend the prior work to optimize adaptive sequential designs over a range of geometric mean test/reference ratios (GMRs) of 70–143% within each of two ranges of intra‐subject coefficient of variation (10–30% and 30–55%). These designs also introduce a futility decision for stopping the study after the first stage if there is sufficiently low likelihood of meeting bioequivalence criteria if the second stage were completed, as well as an upper limit on total study size. The optimized designs exhibited substantially improved performance characteristics over our previous adaptive sequential designs. Even though the optimized designs avoided undue inflation of type I error and maintained power at 80%, their average sample sizes were similar to or less than those of conventional single stage designs. Copyright © 2015 John Wiley & Sons, Ltd.     

Internal Migration and Crime in the Soviet Union

This paper analyses the changes in ethnic self-identification of the population of Ukraine from the last (January 1989) Soviet census to the first (December 2001) Ukrainian census. It begins with a comparison of the census data and describes the remarkable changes observed. Given the incomplete nature of published data on international migrations and their differentiation by ethnic groups in the inter-census period, the paper applies a method to fill in the gaps and calculate net migration balances for each ethnic group. Also, since no data is available on the net reproductive rates for separate ethnic groups in Ukraine, it sets out a method to estimate net reproduction rates for Ukrainians and Russians in the inter-census period. Using these methods, it establishes that differences in net migration on the one hand and the differences in net reproduction on the other contributed 11.1 and 4.4 percent of the growth in the share of Ukrainians and 6.8 and 5.2 percent in the sizeable decline in the share of Russians. The remaining lion’s share is a shift in identity among members of ethnically mixed (mainly Russian-Ukrainian) families. Mothers of ethnically mixed families, identifying the ethnicity of their newly born, contributed 11.4 percent to the Ukrainian gain and 9.2 percent to the Russian loss. The remaining 73.1 percent of the Ukrainian gain and 78.8 percent of Russian loss resulted from lifetime identity shift from Russian to Ukrainian, the most likely candidates being members of Russian-Ukrainian families.     

Experience with a criterion for the classification of johnson distributions

We use simulation to investigate the choice of percentiles when using the criterion given by Bowman and Shenton (1989) to select between Johnson's SB and STJ distributions for a data set. We also look at the choice of a tolerance level in classifying distributions as Johnson's SL-     

Qualitative Risk Assessment of the Acquisition of Meticillin‐Resistant Staphylococcus aureus in Pet Dogs

This article presents a qualitative risk assessment of the acquisition of meticillin‐resistant Staphylococcus aureus (MRSA) in pet dogs, representing an important first step in the exploration of risk of bidirectional MRSA transfer between dogs and humans. A conceptual model of the seven potential pathways for MRSA acquisition in a dog in any given 24‐hour period was developed and the data available to populate that model were considered qualitatively. Humans were found to represent the most important source of MRSA for dogs in both community and veterinary hospital settings. The environment was found to be secondary to humans in terms of importance and other dogs less still. This study highlights some important methodological limitations of a technique that is heavily relied upon for qualitative risk assessments and applies a novel process, the use of relative risk ranking, to enable the generation of a defensible output using a matrix combination approach. Given the limitations of the prescribed methods as applied to the problem under consideration, further validation, or repudiation, of the findings contained herein is called for using a subsequent quantitative assessment.     

Pseudo-likelihood inference for clustered binary data

The maximum likelihood procedure to estimate paraneters of a model has scveral attractive properties including the existence of the covariance matrix which yield asymptotic covariances: for a sample size N the asymptotics are in general of order 1/N. Here we give an asymptotic for the skewness of the distribution of the maximum likelihood estimator of a parameter; this is of order 1/ n2 and this expression is new. Applications relate to the parameters of (i) the Poisson, binomial, and normal density. (ii) the gamna density and (iii) the Beta debsity. Other application are being considered. The expression for the asymptotic skowness at one phase of the study tured out to be unusually complicated involving the asymptotic expressions for variance and bias. When these were identified a much simpler compact expression appeared which we now describe. The work is a much improved treatment of the subject described in Shenton and Bowman (Mariunm likelihood estimation in small samples, Griffin. 1977).     

Licensure as a Dilemma for Social Work Education: Findings of a National Study

Abstract

This paper reports on the first national survey to study the perceptions of MSW social work faculty of the relationship between licensing examinations and social work education. A non-random sample of 242 faculty from 39 systematically selected accredited schools from all states with licensure responded. The questionnaire focused on the impact of the national licensure examination on teaching, curriculum, and students. Among the major findings was that students are perceived as regarding the licensure exam as important to the profession and significant to their future. Faculty, however, only take the examination into consideration in the advisement process. Generally, they are unfamiliar with the examination's content, and they disregard it in curriculum development and in teaching.     

Use of population measures and norms to identify resilient outcomes in young people in care: an exploratory study

The purposes of this study were to derive a new method for identifying resilience (i.e. positive adaptation in spite of serious adversity) among young people in care and to determine the percentage of the latter who experienced resilience on selected outcomes, as conceptualized from within the developmental approach of Looking After Children. The participants comprised two samples of young people who were living in out‐of‐home care (mainly foster care) in the province of Ontario, Canada, 340 aged 10–15 years and 132 aged 5–9 years. Virtually all had experienced severe adversity in their families of origin, such that in most cases the legal custody, care, and control of the young people had been permanently transferred from their parents to a local Children's Aid Society. Corresponding to each in‐care sample was a general‐population sample of the same age range that served as a normative comparison group and was drawn from the National Longitudinal Survey of Children and Youth (NLSCY). The NLSCY is an ongoing, long‐term social‐policy study of the development of a nationally representative sample of Canadian children into adolescence and early adulthood. The general‐population samples were composed, respectively, of 5539 young people aged 10–15 years and 11 858 children aged 5–9 years. Resilience among the young people in care was operationally defined, on each outcome variable, as average or above‐average functioning relative to that of the general‐population sample of the same age range. The percentage experiencing resilience was relatively high on the outcomes of health, self‐esteem, and pro‐social behaviour, moderate on the outcomes of relationship with friends and anxiety and emotional distress, and low on the outcome of academic performance. The implications of the findings are discussed.