Constrained nonparametric maximum likelihood estimation of stochastically ordered survivor functions

This paper considers estimators of survivor functions subject to a stochastic ordering constraint based on right censored data. We present the constrained nonparametric maximum likelihood estimator (C‐NPMLE) of the survivor functions in one‐and two‐sample settings where the survivor distributions could be discrete or continuous and discuss the non‐uniqueness of the estimators. We also present a computationally efficient algorithm to obtain the C‐NPMLE. To address the possibility of non‐uniqueness of the C‐NPMLE of $S_1(t)$ when $S_1(t)\le S_2(t)$ , we consider the maximum C‐NPMLE (MC‐NPMLE) of $S_1(t)$ . In the one‐sample case with arbitrary upper bound survivor function $S_2(t)$ , we present a novel and efficient algorithm for finding the MC‐NPMLE of $S_1(t)$ . Dykstra ( 1982 ) also considered constrained nonparametric maximum likelihood estimation for such problems, however, as we show, Dykstra's method has an error and does not always give the C‐NPMLE. We corrected this error and simulation shows improvement in efficiency compared to Dykstra's estimator. Confidence intervals based on bootstrap methods are proposed and consistency of the estimators is proved. Data from a study on larynx cancer are analysed to illustrate the method. The Canadian Journal of Statistics 40: 22–39; 2012 © 2012 Statistical Society of Canada     

Explaining the Motherhood Wage Penalty During the Early Occupational Career

Prior research shows that mothers earn lower hourly wages than women without children, and that this maternal wage penalty cannot be fully explained by differences between mothers and other women in work experience and job characteristics. This research examines whether the residual motherhood wage penalty results from differences between mothers and other women in the accumulation of work interruptions and breaks in schooling. Using longitudinal data for 486 women followed from ages 19 to 31 in the Minnesota Youth Development Study, we find that accumulated months not in the labor force and not enrolled in school explain the residual pay gap between mothers and other women.     

A Simplified Indicator of Social Well-Being in the United States: Examining the Ecological Impact of Family Formation within a County Level Framework

In 1995, a study entitled ??Does Marriage Matter??? was published by Linda Waite in the journal of Demography, which was concerned with the direction of such causal relationships. While Waite??s examination of the causal relationships associated with marriage, and most other analyses of this type, is primarily concerned with the individual level effects of marriage on a variety of outcomes, little is understood concerning the ecological effect of community marriage rates on levels of aggregate well-being. This study aims to contribute to this gap through the implementation of a recent conceptualization of social well-being as a multi-dimensional measure incorporating both biological, operationalized as average life expectancy, and social phenomena, operationalized as, community level crime rates (Raphael, Making the links: what do health promotion, crime prevention, and social development have in common? in 2004). It is important to understand such aggregate level effects in the face of the existing literature, which relies heavily on relational associations which could be subject to ecological fallacy. Analytic techniques incorporate Exploratory Spatial Data Analysis and spatial regression techniques, due to the high existence of spatial autocorrelation often evident in census data, as a way of understanding the effect of the aggregate level marriage rate on the constructed social well being indicator.     

Making Sense of Community Action and Voluntary Participation—A Multilevel Test of Multilevel Hypotheses: Do Communities Act?

To what extent does community context influence individuals’ proclivity to participate in community‐oriented activities and projects? In this article we utilize survey data from residents of 99 Iowa communities to conduct a multilevel analysis of voluntary participation and community action, simultaneously addressing voluntary participation at the individual level and “community action” at the community level. Additionally, we test the suggestion that community attachment may constitute a unique form of social capital. The robustness of these data allows us to overcome the obstacles that have led to the conflation of individual‐ and community‐level attributes in many community studies. We show that community attachment and community‐oriented action are determined almost entirely by individuals’ characteristics rather than by the characteristics of communities, and thus do not constitute community‐level phenomena, calling into question the assumptions on which certain theoretical approaches to community are based.     

The Rheumatoid Arthritis Drug Development Model: a case study in Bayesian clinical trial simulation

The development of a new drug is a major undertaking and it is important to consider carefully the key decisions in the development process. Decisions are made in the presence of uncertainty and outcomes such as the probability of successful drug registration depend on the clinical development programmme. The Rheumatoid Arthritis Drug Development Model was developed to support key decisions for drugs in development for the treatment of rheumatoid arthritis. It is configured to simulate Phase 2b and 3 trials based on the efficacy of new drugs at the end of Phase 2a, evidence about the efficacy of existing treatments, and expert opinion regarding key safety criteria. The model evaluates the performance of different development programmes with respect to the duration of disease of the target population, Phase 2b and 3 sample sizes, the dose(s) of the experimental treatment, the choice of comparator, the duration of the Phase 2b clinical trial, the primary efficacy outcome and decision criteria for successfully passing Phases 2b and 3. It uses Bayesian clinical trial simulation to calculate the probability of successful drug registration based on the uncertainty about parameters of interest, thereby providing a more realistic assessment of the likely outcomes of individual trials and sequences of trials for the purpose of decision making. In this case study, the results show that, depending on the trial design, the new treatment has assurances of successful drug registration in the range 0.044–0.142 for an ACR20 outcome and 0.057–0.213 for an ACR50 outcome. Copyright © 2009 John Wiley & Sons, Ltd.     

Paternal involvement with adolescents in intact families: The influence of fathers over the life course

We measure the quality and quantity of fathers’ involvement with adolescent children in intact families over time using longitudinal data from The National Survey of Children. We examine differentials in fathers’ involvement by children’s and family characteristics and model the long-term effects of fathers’ involvement on children’s outcomes in the transition to adulthood. Fathers are more involved with sons than with daughters and they disengage from adolescents with increasing marital conflict. We find beneficial effects for children of father’s involvement in three domains: educational and economic attainment, delinquent behavior, and psychological well-being. The course of affective relations throughout adolescence also has a beneficial effect on delinquent behavior and psychological well-being.     

Resilience of Cyber Systems with Over‐ and Underregulation

Recent cyber attacks provide evidence of increased threats to our critical systems and infrastructure. A common reaction to a new threat is to harden the system by adding new rules and regulations. As federal and state governments request new procedures to follow, each of their organizations implements their own cyber defense strategies. This unintentionally increases time and effort that employees spend on training and policy implementation and decreases the time and latitude to perform critical job functions, thus raising overall levels of stress. People's performance under stress, coupled with an overabundance of information, results in even more vulnerabilities for adversaries to exploit. In this article, we embed a simple regulatory model that accounts for cybersecurity human factors and an organization's regulatory environment in a model of a corporate cyber network under attack. The resulting model demonstrates the effect of under‐ and overregulation on an organization's resilience with respect to insider threats. Currently, there is a tendency to use ad‐hoc approaches to account for human factors rather than to incorporate them into cyber resilience modeling. It is clear that using a systematic approach utilizing behavioral science, which already exists in cyber resilience assessment, would provide a more holistic view for decisionmakers.     

Nonverbal Communication of Similarity Via the Torso: It’s in the Bag

The human body plays a central role in nonverbal communication, conveying attitudes, personality, and values during social interactions. Three experiments in a large, open classroom setting investigated whether the visibility of torso-located cues affects nonverbal communication of similarity. In Experiments 1 and 2, half the participants wore a black plastic bag over their torso. Participants interacted with an unacquainted same-sex individual selected from a large class who was also wearing (or also not wearing) a bag. Experiment 3 added a clear bag condition, in which visual torso cues were not obscured. Across experiments, black bag-wearing participants selected partners who were less similar to them on attitudes, behaviors, and personality compared to the bag-less—and clear bag—participants. Nonverbal cues in the torso communicate information about similarity of attitudes, behavior, and personality; the center of the body plays a surprisingly central role in early-stage person perception and attraction.     

“Aging males” symptoms and general health of adult males: a cross-sectional study

A cross-sectional study was conducted to explore the prevalence and severity of health-related complaints perceived by adult males of Hong Kong by using the Hong Kong Traditional Chinese versions of the Aging males’ symptoms (AMS) scale and the 5-dimensional and 3-level European Quality of life (EQ-5D-3L) questionnaire. A total of 825 adult males aged 40 years or above were surveyed, and observed that 80% of the population was living with little-to-mild levels of aging symptoms with mean total scores ranged between 26.02?±?7.91 and 32.99?±?7.91 in different age groups. Such symptoms were correlated with age, especially for the somato-vegetative and sexual symptoms. The most severe AMS symptoms were observed in the oldest age group at 70 years or above, with 76%, 34% and 70% living with moderate-to-severe levels of somato-vegetative, psychological and sexual symptoms, respectively. The result was highly correlated with the EQ-5D-3L questionnaire. Secondly, the Hong Kong Aging males’ symptoms (AMS) scale was shown to have good reliability with test–retest coefficient at 0.79 (ranged 0.66–0.87) and Cronbach’s alpha coefficient at 0.88 (ranged 0.70–0.84). In summary, the population of Hong Kong male adults was commonly living with little-to-mild levels of aging symptoms, whereas their severity was correlated with age.