On the efficiency of nonparametric variance estimation in sequential dose-finding

Dose-finding in clinical studies is typically formulated as a quantile estimation problem, for which a correct specification of the variance function of the outcomes is important. This is especially true for sequential study where the variance assumption directly involves in the generation of the design points and hence sensitivity analysis may not be performed after the data are collected. In this light, there is a strong reason for avoiding parametric assumptions on the variance function, although this may incur efficiency loss. In this paper, we investigate how much information one may retrieve by making additional parametric assumptions on the variance in the context of a sequential least squares recursion. By asymptotic comparison, we demonstrate that assuming homoscedasticity achieves only a modest efficiency gain when compared to nonparametric variance estimation: when homoscedasticity in truth holds, the latter is at worst 88% as efficient as the former in the limiting case, and often achieves well over 90% efficiency for most practical situations. Extensive simulation studies concur with this observation under a wide range of scenarios.     

Analyzing Binary Outcome Data with Small Clusters: A Simulation Study

Binary outcome data with small clusters often arise in medical studies and the size of clusters might be informative of the outcome. The authors conducted a simulation study to examine the performance of a range of statistical methods. The simulation results showed that all methods performed mostly comparable in the estimation of covariate effects. However, the standard logistic regression approach that ignores the clustering encountered an undercoverage problem when the degree of clustering was nontrivial. The performance of random-effects logistic regression approach tended to be affected by low disease prevalence, relatively small cluster size, or informative cluster size.     

Bayesian Time Series Analysis of Structural Changes in Level and Trend

In this article we consider the problem of detecting changes in level and trend in time series model in which the number of change-points is unknown. The approach of Bayesian stochastic search model selection is introduced to detect the configuration of changes in a time series. The number and positions of change-points are determined by a sequence of change-dependent parameters. The sequence is estimated by its posterior distribution via the maximum a posteriori (MAP) estimation. Markov chain Monte Carlo (MCMC) method is used to estimate posterior distributions of parameters. Some actual data examples including a time series of traffic accidents and two hydrological time series are analyzed.     

Probing Folk Happiness in Taiwan

This paper examines Taiwan’s folk happiness, which means the subjective well-being of the common people. Subjective well-being of people refers to the judgments people make about their life satisfaction or happiness. Such judgments may include their satisfaction of life as a whole (global life satisfaction) or of specific aspects of life (domain satisfaction). Based on survey data from a large sample, the life satisfaction of people is investigated in two aspects—people’s personal life and their perceived conditions of living in Taiwan, respectively presented as personal well-being and national well-being or societal well-being. The meanings of the well-being findings are interpreted against the socio-political environment of Taiwan. The paper also examines the socio-demographic aspects, including gender, age, marital status, education, income, religion of the folk happiness of Taiwan. It is found that people in Taiwan are moderately happy.     

Trends in Child Poverty in Hong Kong Immigrant Families

In Hong Kong, child poverty is a serious social problem which may lead to intergenerational poverty, but nevertheless only a few studies have examined this issue, particularly for immigrant families. Using Census data (5 %) from 1981, 1991, 2001, and 2011, we assessed child poverty rates in the past three decades and identified key variables contributing to changes in the risk of child poverty for both immigrant and local families. Our results indicate that child poverty rates in Hong Kong-born families have fluctuated between 14.3 and 15.8 % over the past three decades, while for immigrant families they have increased steadily and substantially from 18.1 % in 1981 to 36.5 % in 2001 and then to 37.5 % in 2011. We show that the increase in immigrant child poverty is associated with changes in the Hong Kong economy that have made it more difficult for such families to adapt to the host society, especially in the 1990s and that this negative effect offset the positive influence of compositional changes among this group of immigrant families in terms of parental education levels and family size. The gap between immigrant and local families in terms of child poverty risk is mainly due to the fact that during the 1990s the negative effect of contextual changes in Hong Kong was cancelled out by the beneficial impact of compositional changes for local families, but not for immigrant families where the latter effect was minimal.     

Reducing youth's drug abuse through training social workers for cognitive–behavioral integrated treatment

Cognitive–behavioral integrated treatment (CBIT) is an intervention that social workers can learn to treat youth's drug abuse by cognitive restructuring, behavioral modification, and goal setting. A way to enhance the learning is training specifically for CBIT. Evaluation of the effectiveness of such training in raising social workers' CBIT practice and their young service users' illicit-drug-free days is the aim of this experimental study. This study first randomly assigned 14 outreach social workers to receive training for CBIT and 14 outreach social workers not to receive the training. The study also assessed 222 young service users (aged 11–22 years) engaged by 28 outreach social workers before the training and 169 of them after the training in a six-month follow-up. Furthermore, the study identified the reduction in the youth's dysfunctional cognition of playfulness as a means to deter the youth's drug abuse, based on personal interviews with outreach social workers and their young service users before the training. Derived from the statistical analysis of assessment data, results principally showed cascading effects from the social worker's reception of the CBIT training to the young service user's reception of CBIT, reduced playfulness, and lengthened drug-free days. A supplementary finding was that the young service user's time in the outreach social work service prolonged drug-free days and reduced playfulness. These results imply that the outreach social work service, CBIT training, and CBIT are useful for treating youth's illicit drug abuse.     

Three dimensions of the survival curve: horizontalization,verticalization, and longevity extension

Three dimensions of the survival curve have been developed: (1) "horizontalization," which corresponds to how long a cohort and how many survivors can live before aging-related deaths significantly decrease the proportion of survivors; (2) "verticalization," which corresponds to how concentrated aging-related ("normal") deaths are around the modal age at death (M); and (3) "longevity extension," which corresponds to how far the highest normal life durations can exceed M. Our study shows that the degree of horizontalization increased relatively less than the degree of verticalization in Hong Kong from 1976 to 2001. After age normalization, the highest normal life durations moved closer to M, implying that the increase in human longevity is meeting some resistance.     

The Role of Worker Support and Religious Support in African American Special Needs Adoption: The Bennett Chapel Experience

Between 1998 and 2003 members and friends of Bennett Chapel Missionary Baptist Church in rural East Texas adopted 70 African American special needs children. Data from surveys of 113 Texas and Louisiana adoptive families, including 14 Bennett Chapel families, found that the amount of anticipated worker support influenced the decision to adopt, particularly for Bennett Chapel families, and actual worker support was significantly related to positive adoption impact on the family. Comparisons of Bennett Chapel with other families highlight the uniqueness of this initiative. Findings underscore the importance of worker support for facilitating adoptions in faith and rural communities and increasing adoptions of African American children.     

Psychometric evaluation of the inventory of Gambling Motives,Attitudes and Behaviours (GMAB) among Chinese gamblers

The present study aims to evaluate and refine the Inventory of Gambling Motives, Attitudes and Behaviours (GMAB) specifically designed to assess gambling-related cognitions and behaviours of Chinese gamblers with a random sample of 697 Chinese adults in Macao who were interviewed by telephone. Confirmatory factor analysis generally replicated the basic factor structure of the three domains of GMAB although the removal of several items with low factor loading or cross-loading was suggested. Moreover, the findings supported the addition of another motivational subscale, socialization. The revised version has six subscales of motives (self-worth, monetary gains, sensation seeking, boredom alleviation, learning and socialization), four of attitudes (fate and luck, negative consequences of gambling, techniques and superstition), and five of behaviours (impaired control, gambling involvement, arousal reaction, superstitious behaviour and controlled gambling). The psychometric properties of the revised GMAB (GMAB-R) were demonstrated to be satisfactory.     

Perpetuating Old Exclusions and Producing New Ones: Digital Exclusion in an Information Society

This article presents a study that measures the degree of digital exclusion—or, conversely, the degree of digital inclusion—in Hong Kong, a developed city in East Asia. Governments in the region are among the most active in the developed world in pushing ahead in developing knowledge economies and information societies. The major concern is to improve/maintain their competitiveness in the new knowledge economy created by the process of globalization and the advancement in information technology. Many countries in the region have established themselves in the top ranks of a number of indexes and measurements comparing digital readiness, digital access, information and communication technology penetration, and others. However, not all the citizens in the region share the benefits and promises of the information society. People who are traditionally disadvantaged, such as the elderly and those on a low income, are further excluded from the information society. Such exclusion affects other social groups as well. This study creates a new digital inclusion index to measures the degree of inclusion of various disadvantaged groups in an information society. Data regarding seven disadvantaged groups were collected through a household survey (N = 2,312). The index captures information about access, knowledge, usage, and affordability ininformation and communication technology of the disadvantaged in comparison with mainstream society (N = 284).