Specification testing in nonparametric AR‐ARCH models

In this paper, an autoregressive time series model with conditional heteroscedasticity is considered, where both conditional mean and conditional variance function are modeled nonparametrically. Tests for the model assumption of independence of innovations from past time series values are suggested. Tests based on weighted L²‐distances of empirical characteristic functions are considered as well as a Cramér–von Mises‐type test. The asymptotic distributions under the null hypothesis of independence are derived, and the consistency against fixed alternatives is shown. A smooth autoregressive residual bootstrap procedure is suggested, and its performance is shown in a simulation study.     

Benefits of cultural matching in foster care

Sixty-one foster parents from a central Canadian province participated in a telephone interview that included the question: “What are the benefits of fostering children who have the same values, beliefs and traditions as you?” A total of 51 unique responses were obtained and grouped together by 13 foster parents. Multidimensional scaling and cluster analysis were used to analyze the grouping data. Foster parents described five themes: expand on held values, child feels secure, smooth transitions, low stress and more in common. There were similarities and differences between the perspectives of foster parents interviewed and the literature. Implications for future research are discussed.     

Adolescent Substance Use Prevention Interventions Outside of Classroom Settings

Substance use prevention programs empowering individual adolescents to resist substance use through education and skills training are crucial to reducing substance use within this population. However, existing programs of this type are designed primarily for classroom use, and may not meet the needs of social workers intervening with adolescents outside classroom settings. A literature review identified six programs that have demonstrated statistically significant reductions in substance use when implemented outside the classroom. The current study describes these programs, identifies their common characteristics, and draws on additional prevention research to outline recommendations for practitioners seeking to apply the field’s most current knowledge base in community settings.     

Continued childbearing among women who were pregnant as adolescents

Conclusions The data presented in this paper and the earlier one in this series suggest that the effects of special comprehensive programs for school age mothers are seen most clearly in delay of the first pregnancy subsequent to the programs, as originally indicated by Klerman and Jekel (1973). Rather than terminating childbearing after the second pregnancy, those young mothers who had one subsequent pregnancy usually went on to become pregnant again rather quickly.A question can be raised about the generalizability of the finding from this study which is based on a rather small, black, poverty-lever sample. Although Furstenberg's (1976) results support those of this report in a population with similar characteristics, additional studies of white and non-poverty populations receiving a variety of services are critically needed if the country is to understand the phenomenon of adolescent pregnancy and find effective ways of minimizing its consequences.This study was supported by Grant #MC-R-090357 from the Maternal and Child Health Service, Public Health Service, Dept. of Health, Education and Welfare.     

A Meta-Analysis of Children's Hand-to-Mouth Frequency Data for Estimating Nondietary Ingestion Exposure

Because of their mouthing behaviors, children have a higher potential for exposure to available chemicals through the nondietary ingestion route; thus, frequency of hand-to-mouth activity is an important variable for exposure assessments. Such data are limited and difficult to collect. Few published studies report such information, and the studies that have been conducted used different data collection approaches (e.g., videography versus real-time observation), data analysis and reporting methods, ages of children, locations, and even definitions of "mouthing." For this article, hand-to-mouth frequency data were gathered from 9 available studies representing 429 subjects and more than 2,000 hours of behavior observation. A meta-analysis was conducted to study differences in hand-to-mouth frequency based on study, age group, gender, and location (indoor vs. outdoor), to fit variability and uncertainty distributions that can be used in probabilistic exposure assessments, and to identify any data gaps. Results of this analysis indicate that age and location are important for hand-to-mouth frequency, but study and gender are not. As age increases, both indoor and outdoor hand-to-mouth frequencies decrease. Hand-to-mouth behavior is significantly greater indoors than outdoors. For both indoor and outdoor hand-to-mouth frequencies, interpersonal, and intra-personal variability are approximately 60% and approximately 30%, respectively. The variance difference among different studies is much bigger than its mean, indicating that different studies with different methodologies have similar central values. Weibull distributions best fit the observed data for the different variables considered and are presented in this article by study, age group, and location. Average indoor hand-to-mouth behavior ranged from 6.7 to 28.0 contacts/hour, with the lowest value corresponding to the 6 to <11 year olds and the highest value corresponding to the 3 to <6 month olds. Average outdoor hand-to-mouth frequency ranged from 2.9 to 14.5 contacts/hour, with the lowest value corresponding to the 6 to <11 year olds and the highest value corresponding to the 6 to <12 month olds. The analysis highlights the need for additional hand-to-mouth data for the <3 months, 3 to <6 months, and 3 to <6 year age groups using standardized collection and analysis because of lack of data or high uncertainty in available data. This is the first publication to report Weibull distributions as the best fitting distribution for hand-to-mouth frequency; using the best fitting exposure factor distribution will help improve estimates of exposure. The analyses also represent a first comprehensive effort to fit hand-to-mouth frequency variability and uncertainty distributions by indoor/outdoor location and by age groups, using the new standard set of age groups recommended by the U.S. Environmental Protection Agency for assessing childhood exposures. Thus, the data presented in this article can be used to update the U.S. EPA's Child-Specific Exposure Factors Handbook and to improve estimates of nondietary ingestion in probabilistic exposure modeling.     

Formerly Incarcerated Parents and Their Children

The negative effects of incarceration on child well-being are often linked to the economic insecurity of formerly incarcerated parents. Researchers caution, however, that the effects of parental incarceration may be small in the presence of multiple-partner fertility and other family complexity. Despite these claims, few studies have directly observed either economic insecurity or the full extent of family complexity. We study parent-child relationships with a unique data set that includes detailed information about economic insecurity and family complexity among parents just released from prison. We find that stable private housing, more than income, is associated with close and regular contact between parents and children. Formerly incarcerated parents see their children less regularly in contexts of multiple-partner fertility and in the absence of supportive family relationships. Significant housing and family effects are estimated even after we control for drug use and crime, which are themselves negatively related to parental contact. The findings point to the constraints of material insecurity and the complexity of family relationships on the contact between formerly incarcerated parents and their children.     

The study of urbanization

Seven years' work of the Committee on Urbanization of the Social Science Research Council has produced The Study of Urbanization. Although the book is an excellent series of documentations of trends in specific fields, it lacks any attempt to unify the contributions to a concise definition of urbanization.Most contributors view urbanization as a process of aggregation, but this is no more than a rough indicator of the fundamental processes at work, and each discipline explores only the matter confined to its assigned segment of the process. Thus, for example, the city is viewed as a sub-division of localized space; as a complex of markets for land, labor, housing, and goods and services; or as a set of market-social units. From what is offered in this volume, then, one is led to think that sociology cannot find a comprehensive approach to fashioning a general model of urbanization.While three papers come close to defining urbanization as substance and process and are an orderly account of at least the salient features of urbanization through early, transitional, and late phases, urbanization as a process in different areas and cultures is a subject which is treated casually. While the very concept of urbanization implies the recurrence of common features, a set of criteria for avoiding preoccupation with the exotic and inconsequential in different cultures is still needed. We need to study the significance of the fact that peoples of various parts of the world have entered urbanization at different points in industrial, institutional, and administrative technology. Here, organization, the most commonly agreed upon variable in this book, is not a sufficient explanation.In sum, the subject is too broad for close agreement, but the failure of the book to achieve its objective is counterbalanced by the individual quality of the contributions.