Sequential change detection in the presence of unknown parameters

It is commonly required to detect change points in sequences of random variables. In the most difficult setting of this problem, change detection must be performed sequentially with new observations being constantly received over time. Further, the parameters of both the pre- and post- change distributions may be unknown. In Hawkins and Zamba (Technometrics 47(2):164–173, 2005), the sequential generalised likelihood ratio test was introduced for detecting changes in this context, under the assumption that the observations follow a Gaussian distribution. However, we show that the asymptotic approximation used in their test statistic leads to it being conservative even when a large numbers of observations is available. We propose an improved procedure which is more efficient, in the sense of detecting changes faster, in all situations. We also show that similar issues arise in other parametric change detection contexts, which we illustrate by introducing a novel monitoring procedure for sequences of Exponentially distributed random variable, which is an important topic in time-to-failure modelling.     

We care about care: advice by children in care for children in care,foster parents and child welfare workers about the transition into foster care

Twenty children in foster care, ages 8 to 15 years, provided advice to children in care, foster parents and child welfare workers about ways to assist service delivery during the transition into foster care. The children discussed the importance of tending to experiences such as foster home expectations, the importance of time and information, the new foster/parent–child relationship, coping with stress, the ability to be engaged in decision‐making, the benefits of foster care and the need to build a trusting and personal relationship between children in care and their caregivers. The importance of listening to children's experiences of the transition into foster care and incorporating their advice into future research, policy and practice will be discussed.     

Nonparametric estimation of the multivariate survivor function: the multivariate Kaplan–Meier estimator

The Dabrowska (Ann Stat 16:1475–1489, 1988) product integral representation of the multivariate survivor function is extended, leading to a nonparametric survivor function estimator for an arbitrary number of failure time variates that has a simple recursive formula for its calculation. Empirical process methods are used to sketch proofs for this estimator’s strong consistency and weak convergence properties. Summary measures of pairwise and higher-order dependencies are also defined and nonparametrically estimated. Simulation evaluation is given for the special case of three failure time variates.     

Magazine Coverage of Child Sexual Abuse, 1992–2004

This article analyzes trends in the coverage of child sexual abuse in popular magazines since the early 1990s. The article employs systematic analysis to identify and analyze articles in four popular magazines. Articles are analyzed by subject, length, and publication. The results affirm established theories of newsworthiness related to the coverage of specific stories over time. However, interest in the subject waned in the past 10 years, with the brief and dramatic exception of coverage connected to the Catholic Church in 2002. The findings demonstrate systematic differences between the slants of the four magazines studied. The findings also suggest that child abuse professionals could improve the quality of coverage by agreeing to interviews in connection with articles about childhood sexual abuse.     

Prevalence of classes of risk behaviors for HIV infection in a randomly selected Australian population

A random, geographically stratified sample of over 2,600 individuals aged 16 and over was interviewed in all states and territories of Australia to determine the prevalence of classes of behaviors which are associated with HIV infection. Returns from the anonymous risk behavior questionnaire (60.2% return rate) suggested that the prevalence of both male and female homosexual behavior, and contact with prostitutes, was substantially lower than that estimated by Kinsey et al. (1948, 1953). Data suggest that prevalence of classes of behaviors which place Australian individuals at risk of HIV infection may be lower than American estimates. However, the proliferation of HIV into the Australian homosexual community may be more extensive than previously assumed. The implications of these data for HIV preventive education programs and their targeting are discussed.     

Family policy and couples’ labour supply: an empirical assessment

This paper empirically examines the effect on couples’ labour supply of a universal at-birth cash benefit and a government subsidy equal to 50% of child care expenditure for working parents. The method is first to simulate the effects on labour supply over the adult lifecycle using a calibrated dynamic utility maximisation model of a representative couple, using data drawn from waves of a longitudinal survey for Australia. Then using the same data, the effect of family benefits and the child care subsidy on couples’ hours worked is econometrically estimated. The 50% child care subsidy was found to increase the average couple’s labour supply by the equivalent of 0.75 to 1 h per week whilst children are of pre-school age, and less on average over the couple’s working lifetime. The cash benefit changes were found to have a negligible effect on labour supply.     

A National Survey on Depression,Internalized Homophobia,College Religiosity,and Climate of Acceptance on College Campuses for Sexual Minority Adults

ABSTRACT

Sexual minority persons have an increased risk for negative mental health outcomes in adulthood. This seems to largely be due to experiences of stigma in social settings. This study sought to understand the relationship between attending a religiously conservative college, internalized homophobia (a measure of sexual stigma), and depressive symptoms for sexual minority adults. Sexual minority adult participants (n = 384) from across the U.S. were recruited and completed a Web-based, anonymous survey. A mediation model predicting depression through college religious conservatism, college acceptance of sexual minority identities, and internalized homophobia was tested using path analysis. Results revealed an indirect effect of increased religious conservatism of a college predicted higher depression through lower college acceptance and higher internalized homophobia. Implications for the mental health of sexual minority adults and future research are examined.     

The demographic assessment of family planning programs: a bibliographic essay

Over the past 15-20 years a substantial literature has accumulated in the area of determining the effect of family planning programs upon fertility, and a selected bibliography is provided. The development of modern contraceptive techniques coincided with the development of large national programs designed to reduce the fertility of the general population, and literature is presented on each of the several evaluation methods that have been used to examine program-induced changes in 1 or more fertility measures. 2 methods deal with data on individuals - births averted among acceptors and individual matching; the latter compares the fertility experience of acceptors and matched non-acceptors. A different class of methods is aggregated methods. Either areas and areal variables are the focus of the analysis proceeds with measures on general subgroups identified by such factors as residence, age, or marital status. The aggregate methods are multiple regression, program experiemnts, matching of areas, correspondence between program activity and fertility change, decomposition, and simulation. The disparity in methods has conspired with large differences in programs, data sets, and investigator interests to produce serious problems of non-comparability in results.