A comparative study of tests for paired lifetime data

In this paper, we investigate different procedures for testing the equality of two mean survival times in paired lifetime studies. We consider Owen’s M-test and Q-test, a likelihood ratio test, the paired t-test, the Wilcoxon signed rank test and a permutation test based on log-transformed survival times in the comparative study. We also consider the paired t-test, the Wilcoxon signed rank test and a permutation test based on original survival times for the sake of comparison. The size and power characteristics of these tests are studied by means of Monte Carlo simulations under a frailty Weibull model. For less skewed marginal distributions, the Wilcoxon signed rank test based on original survival times is found to be desirable. Otherwise, the M-test and the likelihood ratio test are the best choices in terms of power. In general, one can choose a test procedure based on information about the correlation between the two survival times and the skewness of the marginal survival distributions.     

Parental grief in three societies: networks and religion as social supports in mourning

How do people respond to the grief of parents over the death of their infant child? This article documents the experience of one of the authors, an American married to a Russian whose child died in England. Responses to this death by friends, colleagues and family in the USA, England, and two cities in Russia varied considerably in terms of depth and degree of engagement (emotional engagement, respect, or distance and avoidance). What factors underlie these varied responses? Two are identified, one structural, the other cultural: the strength of the social ties within social networks, and religiosity as historically sedimented within a culture. The degree of engagement is correlated with network form; but the content of engagement depends on religiosity.     

Exploring Potential 'Extra-Familial' Child Homicide Assailants in the UK and Estimating their Homicide Rate: Perception of Risk--The Need for Debate

High-profile child murders lead parents to fear for their children’ssafety, but perception of risk is often at variance with reality.We explore the numbers of potential ‘Extra-familial’child homicide assailants in the United Kingdom and estimatetheir actual murder rate to determine risk levels. A South ofEngland study, equivalent to a 4 per cent sample of the UK population,of a decade of consecutive child homicides identified the characteristicsof child homicide assailants, finding that the most frequentassailants—the ‘Intra-familial’—werevery different from ‘Extra-familial’ assailants.‘Extra-familial’ killers were all males, aged nineteento forty-two, with convictions for Violent-Multi-Criminal-Child-Sex-Abuse(VMCCSA) offences and Multi-Criminal-Child-Sex-Abuse (MCCSA),whose victims were aged seven-plus years. Projecting these characteristicsonto the male UK population enables us to estimate the numbersof potential UK ‘Extra-familial’ assailants, whichare set against known UK child (five to fourteen) homicides(WHO, 2005). To account for any ‘hidden’ child homicides,deaths in the ‘undetermined’ violent death category,designated ‘Other External Cause’ (OEC), are calculatedto provide a ‘maximum’ child homicide rate. Therewere potentially 912 VMCCSA and 886 MCCSA ‘Extra-familial’offenders in the United Kingdom, who could be responsible forthe WHO-reported UK three-year average of ‘Extra-family’fifteen child homicide and seventeen OEC deaths per annum; ahomicide rate of 12,061 per million (pm) for VMCCSA and 3,386pm for MCSA, which is 1.21 and 0.34 per cent; however, the VMCCSAhomicide rate was 403 times greater than the all children accidentand cancer death rates. Though the vast majority of these potentialassailants did not kill, comparatively, they are extremely dangerous.Practice and ethical issues are debated, which considers activeoutreach for the ‘treatable’ to possible ‘reviewable’custodial sentences for the VMCCSA.     

Paradoxes of Sexuality,Gay Identity,and the Closet

In this project, I illustrate how eight premises of sexuality, gay identity, and the closet contribute to the existence of paradox, an interactional situation constituted by contradiction. I first outline the following premises: gay identity is (1) inextricably tied to the metaphor of the closet; coming out is necessary when gay identity (2) is invisible; the closet draws meaning (3) only in relation to heteronormative contexts; gay identity, as a (4) stigmatized identity, makes coming out a (5) potentially dangerous act; coming out is conceived of as a (6) necessary and important, (7) discrete and linear, (8) inescapable and ever‐present process. I then use autoethnography to describe and analyze the lived experience of paradox in terms of these premises. I conclude by formulating ways a gay person can negotiate paradox in, and by way of, interaction.     

A statistician's perspective on biomarkers in drug development

Biomarkers play an increasingly important role in many aspects of pharmaceutical discovery and development, including personalized medicine and the assessment of safety data, with heavy reliance being placed on their delivery. Statisticians have a fundamental role to play in ensuring that biomarkers and the data they generate are used appropriately and to address relevant objectives such as the estimation of biological effects or the forecast of outcomes so that claims of predictivity or surrogacy are only made based upon sound scientific arguments. This includes ensuring that studies are designed to answer specific and pertinent questions, that the analyses performed account for all levels and sources of variability and that the conclusions drawn are robust in the presence of multiplicity and confounding factors, especially as many biomarkers are multidimensional or may be an indirect measure of the clinical outcome. In all of these areas, as in any area of drug development, statistical best practice incorporating both scientific rigor and a practical understanding of the situation should be followed. This article is intended as an introduction for statisticians embarking upon biomarker-based work and discusses these issues from a practising statistician's perspective with reference to examples.     

The social dimensions of happiness and life satisfaction of Australians: Evidence from the World Values Survey

Relatively short‐term verbal therapies and other forms of intervention may help people to overcome difficult passages in life, but studies in recent decades have pointed to the salience of social and economic conditions in shaping life satisfaction and happiness. The present study contributes to our knowledge of this field by extending the range of social factors considered, but also, crucially, by the employment of statistical analyses that serve to disentangle the often overlapping variables associated with life satisfaction and happiness. Our results support previous ‘demographic’ findings as well as new results including education, marriage, children, human rights and, particularly in the context of Australian society, perceived choice in life. Establishing what the major contributing factors are can assist the formulation of social policy. Moreover, it can alert practitioners to the value of consolidating their work by encouraging service users to utilise community sources that enhance life satisfaction and/or happiness. Key Practitioner Message: ● The informed linking of service users to sources of life satisfaction and happiness can ‘value add’ direct service interventions; ● The salience of exercising individual choice to achieving life satisfaction reinforces the importance of the practice principle of self‐determination; ● A person's sense of physical wellbeing is a relevant part of social assessment and subsequent planned actions.     

Marginal Correlation from Logit- and Probit-Beta-Normal Models for Hierarchical Binary Data

In hierarchical data settings, be it of a longitudinal, spatial, multi-level, clustered, or otherwise repeated nature, often the association between repeated measurements attracts at least part of the scientific interest. Quantifying the association frequently takes the form of a correlation function, including but not limited to intraclass correlation. Vangeneugden et al. (2010 Vangeneugden, T., Molenberghs, G., Laenen, A., Geys, H., Beunckens, C., Sotto, C. (2010). Marginal correlation in longitudinal binary data based on generalized linear mixed models. Communi. Stati. Theory &; Methods. 39:3542–3557. [Google Scholar]) derived approximate correlation functions for longitudinal sequences of general data type, Gaussian and non-Gaussian, based on generalized linear mixed-effects models. Here, we consider the extended model family proposed by Molenberghs et al. (2010 Molenberghs, G., Verbeke, G., Demétrio, C., Vieira, A. (2010). A family of generalized linear models for repeated measures with normal and conjugate random effects. Stat. Sci. 25:325–347.[Crossref], [Web of Science ®] , [Google Scholar]). This family flexibly accommodates data hierarchies, intra-sequence correlation, and overdispersion. The family allows for closed-form means, variance functions, and correlation function, for a variety of outcome types and link functions. Unfortunately, for binary data with logit link, closed forms cannot be obtained. This is in contrast with the probit link, for which such closed forms can be derived. It is therefore that we concentrate on the probit case. It is of interest, not only in its own right, but also as an instrument to approximate the logit case, thanks to the well-known probit-logit ‘conversion.’ Next to the general situation, some important special cases such as exchangeable clustered outcomes receive attention because they produce insightful expressions. The closed-form expressions are contrasted with the generic approximate expressions of Vangeneugden et al. (2010 Vangeneugden, T., Molenberghs, G., Laenen, A., Geys, H., Beunckens, C., Sotto, C. (2010). Marginal correlation in longitudinal binary data based on generalized linear mixed models. Communi. Stati. Theory &; Methods. 39:3542–3557. [Google Scholar]) and with approximations derived for the so-called logistic-beta-normal combined model. A simulation study explores performance of the method proposed. Data from a schizophrenia trial are analyzed and correlation functions derived.