An Introduction to Practical Sequential Inferences via Single-Arm Binary Response Studies Using the binseqtest R Package

We review sequential designs, including group sequential and two-stage designs, for testing or estimating a single binary parameter. We use this simple case to introduce ideas common to many sequential designs, which in this case can be explained without explicitly using stochastic processes. We focus on methods provided by our newly developed R package, binseqtest, which exactly bound the Type I error rate of tests and exactly maintain proper coverage of confidence intervals. Within this framework, we review some allowable practical adaptations of the sequential design. We explore issues such as the following: How should the design be modified if no assessment was made at one of the planned sequential stopping times? How should the parameter be estimated if the study needs to be stopped early? What reasons for stopping early are allowed? How should inferences be made when the study is stopped for crossing the boundary, but later information is collected about responses of subjects that had enrolled before the decision to stop but had not responded by that time? Answers to these questions are demonstrated using basic methods that are available in our binseqtest R package. Supplementary materials for this article are available online.     

Properties of two tests for outliers in multivariate data

Mardia's multivariate kurtosis and the generalized distance have desirable properties as multivariate outlier tests. However, extensive critical values have not been published heretofore. A published approximation formula for critical values of the kurtosis is shown to inadequately control the type I error rate, with observed error rates often differing from their intended values by a factor of two or more. Critical values derived from simulations for both tests for up to 25 dimensions and 500 observations are presented. The power curves of both tests are discussed. The generalized distance is the more powerful test when exactly one outlier is present and the contaminant is substantially mean-shifted. However, as the number of outliers increases, the kurtosis becomes the more powerful test. The two tests are compared with respect to power and vulnerability to masking. Recommendations for the use of these tests and interpretation of results are given.     

Loss and restoration in later life: an examination of dual process model of coping with bereavement

The Dual Process Model (DPM) of Coping with Bereavement identified two oscillating coping processes, loss and restoration (Stroebe & Schut, 1999). The utility of the model is investigated in two studies. In the first, we carried out secondary analyses on a large-scale qualitative study that we had conducted previously. In the second, we conducted a small-scale study specifically examining the DPM. In the first study we re-examined the interviews for Loss- (LO) and Restoration-Oriented (RO) Coping and examined whether these were associated with psychological adjustment. The results showed that those adjusting well reported the stressors New Roles/Identities/ Relationships and Intrusion of Grief significantly more. Those adjusting less well reported the stressors Denial/Avoidance of Restoration Changes and Distraction/Avoidance of Grief significantly more. In the second study, we asked participants about four RO stressors of the DPM: Attending to Life Changes; New Roles/Identities/Relationships; Distraction from Grief; and New Activities. These data showed that not all participants experienced all aspects of RO Coping. In particular, participants had diverse views about the utility of Distraction from Grief as a coping mechanism. The article concludes by discussing the challenges of testing the DPM empirically.     

Impact of Adult Sons’ Incarceration on African American Mothers’ Psychological Distress

This longitudinal study examines the effect of sons’ incarceration on their mothers’ psychological distress. Interviews were conducted over the life course with a community cohort of African American mothers who had children in first grade in 1966 – 1967 when the study began (N =615). Thirty years later, their sons had significant rates of incarceration (22.4%). Structural equation modeling showed that the more recent the incarceration, the greater the mothers’ psychological distress, even controlling for earlier socioeconomic status and psychological well‐being. Financial difficulties and greater burden of grandparenting are associated with having a son incarcerated and they mediate the relationship between the incarceration and a mother’s psychological distress. Results suggest that incarceration has important effects on family members’ well‐being.     

On the structure of subjective well-being

This paper reviews literature on the structure of subjective well-being, and examines the support for a number of proposed well-being dimensions. It is considered that a distinction between cognitive and affective dimensions is conceptually useful, but poorly researched. Clear support, however, is available for a distinction between positive and negative affective dimensions, as well as for a general second-order dimension of subjective well-being. Proposals for a distinction between inner and outer dimensions of well-being are considered promising but speculative at present. Although the intensity and frequency of affective experience are clearly distinct, it is considered that affect intensity should not be regarded as a dimension of well-being. Three issues related to the dimensionality of well-being, the time focus of assessment, attempts at cross-classification of dimensions, and research on the stability of well-being structure, are also discussed. Although considerable research into subjective well-being exists, the structure of well-being is not yet well established or researched.     

Low‐Probability Flood Risk Modeling for New York City

The devastating impact by Hurricane Sandy (2012) again showed New York City (NYC) is one of the most vulnerable cities to coastal flooding around the globe. The low‐lying areas in NYC can be flooded by nor'easter storms and North Atlantic hurricanes. The few studies that have estimated potential flood damage for NYC base their damage estimates on only a single, or a few, possible flood events. The objective of this study is to assess the full distribution of hurricane flood risk in NYC. This is done by calculating potential flood damage with a flood damage model that uses many possible storms and surge heights as input. These storms are representative for the low‐probability/high‐impact flood hazard faced by the city. Exceedance probability‐loss curves are constructed under different assumptions about the severity of flood damage. The estimated flood damage to buildings for NYC is between US$59 and 129 millions/year. The damage caused by a 1/100‐year storm surge is within a range of US$2 bn–5 bn, while this is between US$5 bn and 11 bn for a 1/500‐year storm surge. An analysis of flood risk in each of the five boroughs of NYC finds that Brooklyn and Queens are the most vulnerable to flooding. This study examines several uncertainties in the various steps of the risk analysis, which resulted in variations in flood damage estimations. These uncertainties include: the interpolation of flood depths; the use of different flood damage curves; and the influence of the spectra of characteristics of the simulated hurricanes.     

Natural family planning: A comparison of continuers and discontinuers

Little research has been done on social-psychological variables related to the use of natural family planning. The objective of this study was to analyze variables that differentiated between continuers and discontinuers of natural family planning (NFP). Questionnaires were obtained from couples who had received instruction in the sympto-thermal method of natural family planning at a large urban hospital. Subjects who were attempting to become pregnant or who were using other methods of contraception in conjunction with NFP were deleted from the analysis, leaving N of 74. With Pearson correlation, variables significantly related (p<.05) to NFP continuance were: religiosity, planning more children, perceived severity of pregnancy, support from spouse and relatives, dissatisfaction with other contraceptive methods, attitudes toward NFP, perceived effectiveness of NFP, attitudes toward abstinence, and importance of intercourse.     

Interrogating Racialized Global Labour Supply: An Exploration of the Racial/National Replaceme of Foreign Agricultural Workers in Canada*

Dans cet article, on analyse le remplacement des travailleurs antillais par des Mexicains dans le Programme des travailleurs agricoles saisonniers du gouvernement du Canada, en mettant l'accent sur le rôle des interprétations racialisées dans la mise en ?uvre de ce genre de programme. On y soutient qu'un mécanisme de racialisation étaie les discours des agriculteurs ontariens à la recherche de la main‐d ?uvre la plus laborieuse, fiable et flexible. Parfois même, les discours des agriculteurs affichent un racisme grossier, dépeignant les honimes antillais comme des Noirs hypersexués qui présentent un risque pour les Canadiennes, alors que, d'autres fois, ces préjugés raciaux sont formulées en termes de prédispositions physiques ou psychologiques à travailler à certaines récoltes. This paper analyses the replacement of Caribbean workers by Mexicans in Canada's Seasonal Agricultural Workers Program, highlighting the role of racialized understandings in implementing foreign worker programs. It argues that a process of racialization underpins the discourses employed by Ontario growers in search of the most hardworking, reliable and flexible labour force. Sometimes grower discourses manifest a crude racism, casting Caribbean men as hypersexualized Black subjects who pose a risk to Canadian women, while other times these racialized assumptions are framed in terms of physical and/or psychic dispositions to the production of certain crops.     

Development of Pre-Word-Learning Skills in Infants with Cochlear Implants

Families of infants who are congenitally deaf now have the option of cochlear implantation at a very young age. In order to assess the effectiveness of early cochlear implantation, however, new behavioral procedures are needed to measure speech perception and language skills during infancy. One important component of language development is word learning-a complex skill that involves learning arbitrary relations between words and their referents. A precursor to word learning is the ability to perceive and encode intersensory relations between co-occurring auditory and visual events. Recent studies in infants with normal hearing have shown that intersensory redundancies, such as temporal synchrony, can facilitate the ability to learn arbitrary pairings between speech sounds and objects (Gogate & Bahrick, 1998). To investigate the early stages of learning arbitrary pairings of sounds and objects after cochlear implantation, we used the Preferential Looking Paradigm (PLP) to assess infants' ability to associate speech sounds to objects that moved in temporal synchrony with the onset and offsets of the signals. Children with normal hearing ranging in age from 6, 9, 18, and 30 months served as controls and demonstrated the ability to learn arbitrary pairings between temporally synchronous speech sounds and dynamic visual events. Infants who received their cochlear implants (CIs) at earlier ages (7-15 months of age) performed similarly to the infants with normal hearing after about 2-6 months of CI experience. In contrast, infants who received their implants at later ages (16-25 months of age) did not demonstrate learning of the associations within the context of this experiment. Possible implications of these findings are discussed.