The fiducial argument and hacking's principle of irrelevance

In a searching analysis of the fiducial argument Hacking (1965) proposed the Principle of Irrelevance as a condition under which the argument is valid. His statement of the Principle was essentially non-mathematical and this paper presents a mathematical development of the Principle. The relationship with likelihood inference is explored and some of the proposed counter-examples to fiducial theory are considered. It is shown that even with the Principle of Irrelevance examples of non-uniqueness of fiducial distributions exist.     

Hellinger distance as a penalized log likelihood

The present paper studies the minimum Hellinger distance estimator by recasting it as the maximum likelihood estimator in a data driven modification of the model density. In the process, the Hellinger distance itself is expressed as a penalized log likelihood function. The penalty is the sum of the model probabilities over the non-observed values of the sample space. A comparison of the modified model density with the original data provides insights into the robustness of the minimum Hellinger distance estimator. Adjustments of the amount of penalty leads to a class of minimum penalized Hellinger distance estimators, some members of which perform substantially better than the minimum Hellinger distance estimator at the model for small samples, without compromising the robustness properties of the latter.     

Notes on likelihood intervals and profiling

In many applications, decisions are made on the basis of function of parameters g(θ). When the value of g(theta;) is calculated using estimated values for te parameters, its is important to have a measure of the uncertainty associated with that value of g(theta;). Likelihood ratio approaches to finding likelihood intervals for functions of parameters have been shown to be more reliable, in terms of coverage probability, than the linearization approach. Two approaches to the generalization of the profiling algorithm have been proposed in the literature to enable construction of likelihood intervals for a function of parameters (Chen and Jennrich, 1996; Bates and Watts, 1988). In this paper we show the equivalence of these two methods. We also provide and analysis of cases in which neither profiling algorithm is appropriate. For one of these cases an alternate approach is suggested Whereas generalized profiling is based on maximizing the likelihood function given a constraint on the value of g(θ), the alternative algorithm is based on optimizing g(θ) given a constraint on the value of the likelihood function.     

Locally quadratic log likelihood and data-based transformations

The investigation of multi-parameter likelihood functions is simplified if the log likelihood is quadratic near the maximum, as then normal approximations to the likelihood can be accurately used to obtain quantities such as likelihood regions. This paper proposes that data-based transformations of the parameters can be employed to make the log likelihood more quadratic, and illustrates the method with one of the simplest bivariate likelihoods, the normal two-parameter likelihood.     

Continuity and change in work-life balance choices

This paper explores the ways in which the work-life balance choices made by heterosexual couples differ in different generations, how such choices are gendered, and the extent to which 'individualization' provides an adequate conceptualization of the effects of social change on heterosexual couples. It argues that processes of individualization need to be seen in the context of changing social institutions, and that it is the de-institutionalization of 'the family' and the life course that is leading to a de-gendering of work-life balance choices. The paper draws on findings from a restudy of the family and social change and a study of the gender dimensions of job insecurity both of which were carried out in the same geographical location. The studies provide evidence of generational change in work-life balance choices and increasing occupational differentiation between heterosexual partners. This leads to a situation where increasingly choices are made which blur gendered boundaries and which has been made possible by a process of de-institutionalization of the male breadwinner family. Our findings support the contention that processes of individualization are more apparent amongst younger than older generations and that, because of changes external to the family, there is more negotiation and pragmatism amongst younger generations about work-life choices.     

The Untold Story of 50 Years of Adolescent Fertility in West Africa: A Cohort Perspective on the Quantum,Timing, and Spacing of Adolescent Childbearing

Although recent studies examine overall fertility trends in West Africa, few using advanced demographic techniques focus on adolescents. This study explores long‐term patterns of adolescent childbearing in 12 West African countries using 51 Demographic and Health Surveys covering birth cohorts that span 54 years (1940–1994). We employ classic demographic measures as well as disaggregation by early‐ (10–14 years old), middle‐ (15–17), and late adolescence (18–19). Cohort‐based estimates of total adolescent births, parity progression ratios, and rapid repeat birth probabilities reveal little change over time. Most women begin childbearing in adolescence, the progression to additional adolescent births remains common, and the incidence of rapid repeat births is high. In recent cohorts, women exit adolescence with an average of between 0.4 (Ghana) to 1.3 (Niger) births. Contrary to common assumptions, it is women commencing motherhood in early‐ and middle‐, not later adolescence, who account for most West African adolescent fertility.     

Teaching International Social Work in a Global Classroom

Social work educators are challenged with preparing students for international social work and work with immigrant and refugee populations. This pilot project aimed to develop an online global classroom to teach an international social work course to social work students participating from five different locations: United States (N=25), South Africa (N=4), Mexico (N=11), Hong Kong (N=6), and Australia (N=2). Qualitative data were collected from students regarding their experiences in this global classroom. Thematic analysis revealed the development of rich authentic learning, where their interactions with international classmates led to a transformative learning experience and a beginning sense of social work in a global context. Implications for future leaning and teaching of social work content across global borders are discussed.