Batch sampling to improve power in a community trial. Experience from the Pawtucket Heart Health Program

Experiments involving large social units, such as schools, work sites, or whole cities, are commonly limited in statistical power because the number of randomized units is small, leaving few degrees of freedom for residual (between-unit) error. The authors describe a method for increasing residual degrees of freedom in a community experiment without substantially increasing cost or difficulty. In brief, they propose that the experimental units should be divided into random subsamples (batches). Batch sampling can improve statistical power if the community endpoint means are stable over time or if their temporal variation is comparable in period to the batch-sampling schedule. The authors demonstrate the theoretical advantages of the batch system and illustrate its use with data from the Pawtucket Heart Health Program, in which such a design was implemented.     

Bounding Optimal Expected Revenues for Assortment Optimization under Mixtures of Multinomial Logits

We consider assortment problems under a mixture of multinomial logit models. There is a fixed revenue associated with each product. There are multiple customer types. Customers of different types choose according to different multinomial logit models whose parameters depend on the type of the customer. The goal is to find a set of products to offer so as to maximize the expected revenue obtained over all customer types. This assortment problem under the multinomial logit model with multiple customer types is NP‐complete. Although there are heuristics to find good assortments, it is difficult to verify the optimality gap of the heuristics. In this study, motivated by the difficulty of finding optimal solutions and verifying the optimality gap of heuristics, we develop an approach to construct an upper bound on the optimal expected revenue. Our approach can quickly provide upper bounds and these upper bounds can be quite tight. In our computational experiments, over a large set of randomly generated problem instances, the upper bounds provided by our approach deviate from the optimal expected revenues by 0.15% on average and by less than one percent in the worst case. By using our upper bounds, we are able to verify the optimality gaps of a greedy heuristic accurately, even when optimal solutions are not available.     

Female fertility history and mid-late-life health: Findings from China

China’s middle-aged and older women suffer from poorer health than men. Using national baseline data from the China Health and Retirement Longitudinal Study (CHARLS), a survey conducted from 2011 to 2012, this article applies logistic models to investigate the association between female fertility history (parity, early childbearing, late childbearing) and middle-aged and late-life health. We find that parity is related to the mid-late-life health of women. Women with four children or more are more likely to suffer from activities of daily living (ADL) impairment and poorer self-rated health than those with one to three children. Early childbearing is associated with ADL impairment; however, the correlation is mediated by socioeconomic status. Early childbearing is related to self-rated health in later life by an indirect-only mediation effect via educational attainment and personal income.     

DYSFUNCTIONAL MARITAL CONFLICT: AN INTEGRATIVE INTERPERSONAL-INTRAPSYCHIC MODEL*

An integrative interpersonal-intrapsychic model of dysfunctional marital conflict is presented and research support for the model is reviewed. The therapeutic applications of the model are discussed and illustrated with a clinical example.     

农民工的社会网络结构分析

采用2005年深圳外来农村流动人口的调查数据,利用指数随机图模型(p * 模型),分析了农民工的社会网络(包括社会支持网和社会讨论网)结构.分析结果显示,农民工社会网络关系稀疏.尤其是社会讨论网;无论在聚敛性还是扩张性方面,农民工社会网络的核心一边缘的局部结构均较明显,且有小团体现象产生;社会支持和社会讨论关系都更可能受到中间人的控制或约束.属性变量对社会支持网的影响较多.而对社会讨论网的影响较少.指数随机图模型为基于社会网络来认识农民工的社会化过程提供了新的方法.     

The Effect of Support Expectations on Prenatal Attachment: An Evidence-Based Approach for Intervention in an Adolescent Population

This study was designed to determine the significant variables predicting prenatal attachment in an adolescent population. Scientifically supported knowledge of the factors enhancing attachment plays a crucial role in assisting social workers and other health care professionals to accurately assess and intervene to decrease pregnancy risks. Previous prenatal attachment studies demonstrated conflicting findings due to problems from using different theoretical frameworks and research methodologies. In order to ensure consistency, this study infused an attachment theory perspective. Bowlby’s attachment theory, Levitt’s support expectations model, and research from prenatal relationship studies were integrated. The social survey sampled 129 minority status pregnant adolescents attending public school. Measurements included the Prenatal Attachment Inventory (PAI) and the Support Expectations Index (SEI). Regression analyses revealed that support expectation was a powerful predictor of prenatal attachment with pregnancy planning and less stress adding importantly to explain over 33% of the variance. Support expectation was a greater predictor of prenatal attachment than the actual support available. Findings also supported the construct of prenatal attachment as the initial stage of development of the life cycle. Janis B. Feldman is an Assistant Professor, University, of Texas-Pan American.     

Family Structure and Quality of Life of Elders in Rural China: The Role of the New Rural Social Pension

Using data from a survey in Ankang district of Shaanxi province of China in 2011, this article examines the protective effect of the New Rural Social Pension (NRSP) on quality of life of rural elders, as well the moderating effect on association between family structure and quality of life. An instrumental variable approach is used. NRSP is shown to significantly improve the quality of life of rural elders, and a robustness check shows that this effect is consistent across different sets of subgroups. Compared with the elders who have at least one son, the quality of life of those who are childless or have only one child is significantly lower. The NRSP is more likely to significantly improve the quality of life of one-child elders. In addition, the associations between the NRSP and the different facets of quality of life of the elders are significant except for the facet of sensory abilities.