Reducing sample size needed for cox-proportional hazards model analysis using more efficient sampling method

Abstract

In general, survival data are time-to-event data, such as time to death, time to appearance of a tumor, or time to recurrence of a disease. Models for survival data have frequently been based on the proportional hazards model, proposed by Cox. The Cox model has intensive application in the field of social, medical, behavioral and public health sciences. In this paper we propose a more efficient sampling method of recruiting subjects for survival analysis. We propose using a Moving Extreme Ranked Set Sampling (MERSS) scheme with ranking based on an easy-to-evaluate baseline auxiliary variable known to be associated with survival time. This paper demonstrates that this approach provides a more powerful testing procedure as well as a more efficient estimate of hazard ratio than that based on simple random sampling (SRS). Theoretical derivation and simulation studies are provided. The Iowa 65+ Rural study data are used to illustrate the methods developed in this paper.     

Sex Related Factors in the Perception of Threatening Facial Expressions

This study replicated and extended previously reported sex differences involving both viewer and target in the recognition of threatening facial expressions. Based on the assumption that the evolved cognitive mechanisms mediating anger recognition would have been designed by natural selection to operate quickly in the interests of survival, brief tachistoscopic presentation of stimulus photographs was used. Additionally, in contrast to prior published studies, the statistical methods of signal detection research were used to control for the confounding effects of non-random guessing. The main hypothesis, that anger posed by males would be more accurately perceived than anger posed by females, was supported. A secondary hypothesis, that female-posed anger would be more accurately perceived by women than by men, received partial support. Testosterone levels, measured inferentially in terms of diurnal cycles, failed to show the hypothesized positive relationship to accuracy of anger perception.     

The price of a loaf of bread: some conceptions of family support*

This paper reports on a case study of one local authority, and illustrates the different definitions of the term ‘family support’ employed by the different agencies within the authority. It provides a framework to analyse the contribution of the agencies according to the assumptions they make about methods and efficacy of intervention and access to and termination of intervention. It contrasts the findings from this framework with a needs based model of ‘family support’. Social work and health services tend to operate within a narrow, historically determined range, focusing most heavily on emotional support and behavioural change; whereas users and some of the other agencies are more likely to raise matters such as income maintenance, child care, leisure and education. The findings of the case study are discussed in relation to resources for families, key issues for the implementation of family support identified during the introduction of the Children Act, 1989, and the relevance of Social Services Inspectorate inspections to these issues. Copyright © 2002 John Wiley & Sons, Ltd.     

The PALS parenting support programme: lessons learned from the evaluation of processes and outcomes

Although there has recently been a rise in parenting support programmes within the UK, only a minority of these programmes have benefited from evaluation of either outcomes or processes. This paper describes the development of the PALS programme (Parents Altogether Lending Support), reporting both on its effectiveness in improving parents' interactions with their children and on the lessons that were learned about embedding such a programme within the local community. Over the 18‐month period of the programme, a total of 17 courses were run, with 75 parents and carers (primarily mothers) participating in the programme overall. Evaluation results indicated that participants enjoyed the course and found it beneficial, particularly in terms of altering their own actions in specific ways that were able to promote better behaviour on the part of their children. Participants also valued the opportunity to share their experiences with other parents. The key lesson identified in regard to the development of parenting programmes concerned the need for the community to feel a sense of ownership for the initiative. Copyright © 2002 John Wiley & Sons, Ltd.     

Book Review: Funding Virtue: Civil Society Aid and Democracy Promotion,Marina Ottaway and Thomas Carothers (eds.), Carnegie Endowment for International Peace,Washington, DC, 2000

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations -     

Existence and Nash implementation of efficient sharing rules for a commonly owned technology

Suppose that a group of individuals owns collectively a technology which produces a consumption good by means of a (possibly heterogeneous) input. A sharing rule associates input contributions with a vector of consumptions that are technologically feasible. We show that the set of allocations obtained by any continuous sharing rule contains Pareto efficient allocations. We also present a mechanism that implements in Nash equilibrium the Pareto efficient allocations contained in an arbitrary sharing rule. Received: 29 June 1998/Accepted: 15 November 2000     

REVIEWS

Bailey, C. E. (Ed.) (2000). Children in therapy: Using the family as a resource. Doherty, W. J. (2001). Take back your marriage: Sticking together in a world that pulls us apart. New York: Guilford. Larson, J. H. (2000). Should we stay together? A scientically proven method for evaluating your relationship and improving its chances for long‐term success. Weiner‐Davis, M. (2001). The divorce remedy: The proven 7‐step program for saving your marriage.     

Life Experiences and Vulnerabilities of Homeless Women: A Comparison of Women Unaccompanied Versus Accompanied by Minor Children, and Correlates with Children's Emotional Distress

The histories and service needs of 2 groups of homeless women, those unaccompanied by minor children (n = 46) and those accompanied by minor children (n = 22), were compared, on the basis of their responses to a biennial survey of homeless people in a midsize city in the southeast United States. Mothers of children aged 2–10 also completed a measure of stress symptoms for their children (n = 20). Irrespective of family status group, problems such as substance abuse, history of mental illness, health problems, chronicity of homelessness, and crime victimization tended to cluster together. The findings also suggest that declining and/or inadequate levels of public benefits, Temporary Assistance to Needy Families, and Medicaid-funded health care in particular, have adversely affected the 2 groups, particularly families with children. The young children in this sample experienced elevated levels of stress, and significant associations were found between children's stress levels and certain risk factors of their mothers. Implications for service delivery are discussed.