Pivotal Quantities Based on Sequential Data: A Bootstrap Approach

A bootstrap algorithm is provided for obtaining a confidence interval for the mean of a probability distribution when sequential data are considered. For this kind of data the empirical distribution can be biased but its bias is bounded by the coefficient of variation of the stopping rule associated with the sequential procedure. When using this distribution for resampling the validity of the bootstrap approach is established by means of a series expansion of the corresponding pivotal quantity. A simulation study is carried out using Wang and Tsiatis type tests and considering the normal and exponential distributions to generate the data. This study confirms that for moderate coefficients of variation of the stopping rule, the bootstrap method allows adequate confidence intervals for the parameters to be obtained, whichever is the distribution of data.     

An empirical approach to determine a threshold for assessing overdispersion in Poisson and negative binomial models for count data

Overdispersion is a problem encountered in the analysis of count data that can lead to invalid inference if unaddressed. Decision about whether data are overdispersed is often reached by checking whether the ratio of the Pearson chi-square statistic to its degrees of freedom is greater than one; however, there is currently no fixed threshold for declaring the need for statistical intervention. We consider simulated cross-sectional and longitudinal datasets containing varying magnitudes of overdispersion caused by outliers or zero inflation, as well as real datasets, to determine an appropriate threshold value of this statistic which indicates when overdispersion should be addressed.     

Understanding Very Old Age: Looking Back and Thinking Forward

ABSTRACT

Understanding human development among the oldest old is a sequential building process taking into account building-block data, theories, and models from childhood, adulthood, and old age toward a new territory of oldest-old survivors who have lived way beyond the average life-span. A central question is whether the oldest-old survivors have developed specific survival techniques and/or protective environments that nurture survival. Or are the oldest old statistical outliers who by happenstance continue to survive further into old age? This commentary provides a historical framework on the papers in this series that describe challenges confronted by the oldest-old survivors in order to advance our understanding of survival of the oldest old. A clear understanding of the contributors to longevity could guide public policies toward well-being and life satisfaction among our oldest-old citizens.     

Maternal work hours and adolescents’ School outcomes among low-income families in four urban counties

We examine how changes in maternal work hours affect adolescent children's school participation and performance outcomes using data from interviews in 1998 and 2001 with approximately 1700 women who, in May 1995, were welfare-reliant, single mothers of adolescents living in neighborhoods of concentrated poverty in Cuyahoga (Cleveland), Los Angeles, Miami-Dade, and Philadelphia counties. Analyses control for a broad array of mothers' characteristics, including their psychological and physical health, experiences with domestic violence and substance abuse, as well as unobserved time-invariant characteristics. In fixed-effects models, we find unfavorable effects of increased maternal work hours on three of six outcomes: skipping school, performing above average, and parental contact about behavior problems. Adolescent-aged sons seem to be particularly sensitive to changes in mothers' hours of work.     

"MEN I MESS WITH DON'T HAVE ANYTHING TO DO WITH AIDS":

Pivotal in HIV/STD intervention and prevention is how individuals perceive risk. This article discusses how ethnotheory can be used to understand the underpinnings of risk perception from the subject's perspective. Ethnotheory's theoretical and methodological character extends present models used to explain sex-related HIV behaviors and provides insights into risk perception useful for the development of effective intervention strategies. Four detailed ethnographic excerpts from low-income African American and Mexican American men and women illustrate how people form perceptions of risk and how information gained through ethnotheory is useful in the design of culturally relevant interventions.     

Publishers' announcement

Publishers' announcement     

Home care reimbursement for technology-dependent children: Its impact on parental distress

The distress of 52 parents with a technology-dependent child at home is measured using a standardized psychological inventory. Fifty-eight percent of these parents report enough symptoms to classify them as needing psychiatric intervention. Cost savings to third-party payers are accelerating the trend toward home care (rather than institutionalized care). Yet, these findings point to an underestimated cost to families in terms of parents' psychological well-being. One factor associated with less distress for mothers is having services reimbursed through the Medicaid Model Waiver Program, which provides a comprehensive plan for home care services. In contrast, services reimbursed by private third-party payers are more variable, placing greater financial strain and uncertainty on parents, which is associated with greater psychological distress. These results suggest the need for further study of the long-term impact on parents caring for technology-dependent children at home.Reprint requests to Barbara J. Leonard, R.N., Ph.D., Maternal and Child Health Major, Division of Human Development and Nutrition, School of Public Health, Box 197 UMHC, University of Minnesota, Minneapolis, MN 55455, (612) 625-3660.This study was supported in part by BRSG Number 2-S07-RR05448-25 awarded to the University of Minnesota, School of Public Health by the Biomedical Research Grant Program, Division of Research and Resources, National Institute of Health. Additional support was provided by the Department of Health and Human Services, State of Minnesota, Academic Computing Services and Systems, University of Minnesota and special project funds from the University of Minnesota School of Public Health.Barbara J. Leonard is an Assistant Professor and Chair of the Maternal and Child Health Major, Division of Human Development and Nutrition, School of Public Health, University of Minnesota, MN 55455. Her research interests include children with developmental disabilities, their parents, and siblings. She received her Ph.D. from the University of Minnesota.Janny Dwyer Brust is a Research Fellow in the Maternal and Child Health Major at the University of Minnesota. Her research interests include issues related to the care of chronically ill children and sexually abused children. She received her M.P.H. from the University of Minnesota.Joan Patterson is an Assistant Professor in the Maternal and Child Health Major and Associate Director of the Center for Children with Chronic Illness and Disability at the University of Minnesota. Her research interests include family adaptation to chronic illness and family stress and coping. She received her Ph.D. from the University of Minnesota.     

Requests, refusals, and reasons in children's negotiations

Conflict situations were studied as indicators of children's socio-cognitive knowledge and the transmission of values in relation to negotiation. Concepts and paradigms from studies of requests were combined with those from studies of refusals. Puppets were used to create situations that varied (a) as to whether the child makes a request and encounters opposition (requests) or receives a request and offers opposition (refusals), (b) whether the adult offers or does not offer a reason. Children aged 3–5 years (Sample 1, N = 24; Sample 2, N = 24) were encouraged to make a series of attempts at resolving the conflict. Their responses were scored for the level of politeness or strategic skill shown. Request situations elicited higher levels of politeness and strategic skill than did refusal situations. In contrast to disputes in which the other party did not use reasons, the use of a reason by the other party elicited higher level strategies and, when the children were refusing, greater politeness. Some children were able to improve on their first attempt. The improvement was most marked when children were requesting and the adult gave a reason.     

MORAL MESSAGES: THE RELATIVE INFLUENCE OF DENOMINATION ON THE RELIGIOSITY-ALCOHOL RELATIONSHIP

This article examines the use and misuse of alcohol across religious denominations. After controlling for standard sociodemographic variables, we find that the impact of religiosity on alcohol use is greatest among those denominations taking a strong stand against its consumption, mainly because religion constitutes a significant reference group for members. We also find that religiosity fails to influence misuse, and discuss the possible reasons for this result.