AN ADAPTIVE TRIMMED LIKELIHOOD ALGORITHM FOR IDENTIFICATION OF MULTIVARIATE OUTLIERS

This article describes an algorithm for the identification of outliers in multivariate data based on the asymptotic theory for location estimation as described typically for the trimmed likelihood estimator and in particular for the minimum covariance determinant estimator. The strategy is to choose a subset of the data which minimizes an appropriate measure of the asymptotic variance of the multivariate location estimator. Observations not belonging to this subset are considered potential outliers which should be trimmed. For α less than about 0.5, the correct trimming proportion is taken to be that α > 0 for which the minimum of any minima of this measure of the asymptotic variance occurs. If no minima occur for an α > 0 then the data set will be considered outlier free.     

Rating teams and analysing outcomes in one-day and test cricket

Summary.  Multiple linear regression techniques are applied to determine the relative batting and bowling strengths and a common home advantage for teams playing both innings of international one-day cricket and the first innings of a test-match. It is established that in both forms of the game Australia and South Africa were rated substantially above the other teams. It is also shown that home teams generally enjoyed a significant advantage. Using the relative batting and bowling strengths of teams, together with parameters that are associated with common home advantage, winning the toss and the establishment of a first-innings lead, multinomial logistic regression techniques are applied to explore further how these factors critically affect outcomes of test-matches. It is established that in test cricket a team's first-innings batting and bowling strength, first-innings lead, batting order and home advantage are strong predictors of a winning match outcome. Contrary to popular opinion, it is found that the team batting second in a test enjoys a significant advantage. Notably, the relative superiority of teams during the fourth innings of a test-match, but not the third innings, is a strong predictor of a winning outcome. There is no evidence to suggest that teams generally gained a winning advantage as a result of winning the toss.     

A Note on Robustness of the β-Trimmed Mean

Qualitative robustness of the β-trimmed mean has already been observed in terms of relative efficiency and weak continuity of that estimator in neighbourhoods of the exponential distribution. Two more robustness considerations are given here in favour of the β-trimmed mean: the statistical functional representing this estimator is Fréchet differentiable; and it is a special case of the trimmed likelihood estimator. Further, simulations suggest that a fixed proportion of trimming is preferable to adaptive estimation in this case.     

Ambivalence and the paradoxes of grandparenting

This paper focuses on ‘normative talk’ about grandparenting. It is based on a secondary analysis of a study involving 46 interviews with grandparents. It identifies two main cultural norms of grandparenting that emerged from the data –‘being there’ and ‘not interfering’. There were very high levels of consensus in the study that these constituted what grandparents ‘should and should not’ do. However, these two norms can be contradictory, and are not easy to reconcile with the everyday realities of grandparenting. The study found that norms of parenting and also of self determination were also very important for the grandparents in the study. They had a keen sense of what being a ‘good parent’ (to their own adult children) should mean – especially in terms of allowing them to be independent – but this could sometimes conflict with their sense of responsibility to descendant generations of grandchildren. Using the concept of ambivalence and drawing on the accounts of grandparents in the study, the paper explores and offers an explanation for both the coexistence and conflict between different sets of norms, as well as for the remarkably high levels of consensus about ‘being there’ and ‘not interfering’. The paper concludes with a discussion of some of the limitations of the data and the analysis, and with suggestions for the development of further work in this area.     

Reducing attrition in physical activity programs for older adults

This study investigated attrition in a 6-month physical activity intervention for older adults. The program was based on the social-cognitive theory incorporating self-efficacy factors. Two hundred forty-eight insufficiently active 65- to 74-year-olds were recruited from the Australian federal electoral roll. The intervention comprised walking and strength and flexibility exercises and was conducted in 30 local neighborhoods where the participants resided. Characteristics of individuals lost to attrition (n = 86, 35%) were compared with those of program completers (n = 162, 65%). Logistic-regression analysis showed that those lost to attrition came from areas of lower socioeconomic status, were overweight and less physically active, and had lower walking self-efficacy scores and higher loneliness scores. The results suggest that early assessment of these characteristics should be undertaken to identify individuals at risk of attrition, to improve retention, and to avoid potential bias.     

Public crises,public futures

This article begins to map out a novel approach to analysing contemporary contexts of public crisis, relationships between them and possibilities that these scenes hold out for politics. The article illustrates and analyses a small selection of examples of these kinds of contemporary scenes and calls for greater attention to be given to the conditions and consequences of different forms and practices of public and political mediation. In offering a three-fold typology to delineate differences between ‘abject’, ‘audience’ and ‘agentic’ publics the article begins to draw out how political and public futures may be seen as being bound up with how the potentialities, capacities and qualities that publics are imagined to have and resourced to perform. Public action and future publics are therefore analysed here in relation to different versions of contemporary crisis and the political concerns and publics these crises work to articulate, foreground and imaginatively and practically support.     

OPTIMAL DESIGN FOR EARLY‐GENERATION PLANT‐BREEDING TRIALS WITH UNREPLICATED OR PARTIALLY REPLICATED TEST LINES

Some subtle difficulties in optimal design are highlighted by the example of unreplicated field trials laid out on plots with spatial errors defined by uniformity trials. There is a dual problem of the arrangement of control plots and maximizing the number of test‐line entries. A simulation study is conducted by randomizing the allocation of genotypes to the plots of four uniformity trials in accordance with the rules defining a number of competing designs. Results are summarized in terms of the ‘SE ratio’, which reflects the improvement in precision of a given design relative to a completely random design on the same plots. The definition of the SE ratio overcomes problems induced by differential shrinkage and consequent precision of test and control lines. A general result applying to all designs shows a curvilinear improvement in SE ratio with increasing error degrees of freedom of the design. The actual arrangement of check plots is of less importance than their increasing number, which contributes to increasing error degrees of freedom. Overall measures, including expected genetic gain, are used to illustrate the choice of a balance between the total number of test‐line entries and the error degrees of freedom.     

Money management and views of civil partnership in same‐sex couples: results from a UK survey of non‐heterosexuals

Recent legislation in the UK has extended many of the legal and financial rights and responsibilities of heterosexual marriage to same‐sex couples who register their partnerships. Prior to the Civil Partnership Act (2004) however, little was known about financial arrangements in same‐sex couples, nor the extent to which these mirrored those of married or cohabiting heterosexuals. This paper reports the findings from the first large‐scale survey in the UK to investigate finances and civil partnership beliefs in a convenience sample of non‐heterosexuals: 510 individuals, of whom 386 were currently in a same‐sex relationship, participated in the survey. Our findings showed less merging of finances (such as in pooling, allowance, and whole wage systems) than is typical in heterosexual married couples. The results of a series of multinomial logistic regression analyses showed that rating CP as more important, and having both names on the mortgage, significantly reduced the odds of independent (ie, separate) management of finances. Participants were almost unanimous in their endorsement of CP as a form of legal recognition, with a large majority saying that they would also consider it for themselves.