The author introduces robust techniques for estimation, inference and variable selection in the analysis of longitudinal data. She first addresses the problem of the robust estimation of the regression and nuisance parameters, for which she derives the asymptotic distribution. She uses weighted estimating equations to build robust quasi‐likelihood functions. These functions are then used to construct a class of test statistics for variable selection. She derives the limiting distribution of these tests and shows its robustness properties in terms of stability of the asymptotic level and power under contamination. An application to a real data set allows her to illustrate the benefits of a robust analysis. 相似文献
The relation between change points in multivariate surveillance is important but seldom considered. The sufficiency principle is here used to clarify the structure of some problems, to find efficient methods, and to determine appropriate evaluation metrics. We study processes where the changes occur simultaneously or with known time lags. The surveillance of spatial data is one example where known time lags can be of interest. A general version of a theorem for the sufficient reduction of processes that change with known time lags is given. A simulation study illustrates the benefits or the methods based on the sufficient statistics. 相似文献
Conceptions of nationhood (i.e., who is accepted as a member of the national ingroup) are known to be more open in countries with inclusive citizenship and integration policies. Yet, surprisingly, up to now no research has investigated whether the sharedness of these conceptions is related to national policies. Therefore, relying on data from the 2013 International Social Survey Programme, the present study examined to which extent individuals living in 188 regions of 21 European countries share similar conceptions of who is a “true” member of the nation. Both ethnic (e.g., having national ancestry) and civic (e.g., respecting national laws and institutions) criteria were considered. Multilevel analyses revealed that in countries with more inclusive policies (with inclusive citizenship regimes, and where immigrants are granted more political rights) the average regional importance granted to ethnic criteria was lower, and conceptions were more heterogeneous (i.e., less shared). Civic criteria—that are achievable—were deemed more important. This can explain the lower heterogeneity of civic conceptions of nationhood and the lack of impact of national policies (though the average regional importance of these criteria was higher where immigrants had more rights). Overall, these results suggest that inclusive as opposed to exclusive settings leave more room for differing worldviews.
An intraclass correlation coefficient observed in several populations is estimated. The basis is a variance-stabilizing transformation. It is shown that the intraclass correlation coefficient from any elliptical distribution should be transformed in the same way. Four estimators are compared. An estimator where the components in a vector consisting of the transformed intraclass correlation coefficients are estimated separately, an estimator based on a weighted average of these components, a pretest estimator where the equality of the components is tested and then the outcome of the test is used in the estimation procedure, and a James-Stein estimator which shrinks toward the mean. 相似文献
Children with attention‐deficit/hyperactivity disorder (ADHD) exhibit marked difficulty with frequent and intense shifts in negative or positive emotions, referred to as emotional lability. This study examines the relationships between negative emotional lability (NEL), ADHD, and reactive and proactive aggression. A community sample of 96 children (53 with ADHD, 43 control) ages 8–12 and their parents completed a baseline session include a diagnostic structured interview and the Reactive–Proactive Aggression Questionnaire (RPAQ). Parents then rated their child's NEL using the Positive and Negative Affect Scale as part of an Ecological Momentary Assessment protocol 3 times a day for 28 days. Seventy‐three participants (37 with ADHD, 36 control) completed the RPAQ at follow‐up. Hierarchical regression analyses indicated that NEL significantly and independently estimates reactive aggression at baseline and follow‐up, regardless of ADHD status. NEL and ADHD status significantly estimates concurrent proactive aggression, but not at follow‐up. Results of this study suggest that NEL accounts for a significant amount of the variability in reactive aggression, a common difficulty in children with ADHD. Further, individuals that are reportedly emotionally labile become more reactively aggressive over time. Both ADHD diagnostic and NEL are predictors of proactive aggression at baseline, although no interaction occurred. 相似文献
Screen images of old lesbians combine modes of representing female gender, lesbian sexuality, and old age, all of which contain layers of otherness within a hetero-patriarchal and youth-centered society. Analyzing a range of films, from independent to mainstream cinema, this article explores how the ghosted lesbian paradigm intersects with narratives of aging as decline in representations of lesbian characters who are over the age of sixty. The spectral matters of illness, death, mourning, and widowhood inevitably culminate in an unhappy ending. Removed from a lesbian community context, intergenerational continuity vanishes and the old lesbian emerges as the cultural other. 相似文献