Improvement of the quality of the chi-square approximation for the ADF test on a covariance matrix with a linear structure

The asymptotically distribution-free (ADF) test statistic was proposed by Browne (1984). It is known that the null distribution of the ADF test statistic is asymptotically distributed according to the chi-square distribution. This asymptotic property is always satisfied, even under nonnormality, although the null distributions of other famous test statistics, e.g., the maximum likelihood test statistic and the generalized least square test statistic, do not converge to the chi-square distribution under nonnormality. However, many authors have reported numerical results which indicate that the quality of the chi-square approximation for the ADF test is very poor, even when the sample size is large and the population distribution is normal. In this paper, we try to improve the quality of the chi-square approximation to the ADF test for a covariance matrix with a linear structure by using the Bartlett correction applicable under the assumption of normality. By conducting numerical studies, we verify that the obtained Bartlett correction can perform well even when the assumption of normality is violated.     

Second‐order bias‐corrected AIC in multivariate normal linear models under non‐normality

This paper deals with a bias correction of Akaike's information criterion (AIC) for selecting variables in multivariate normal linear regression models when the true distribution of observation is an unknown non‐normal distribution. It is well known that the bias of AIC is $O(1)$ , and there are a number of the first‐order bias‐corrected AICs which improve the bias to $O(n^{-1})$ , where $n$ is the sample size. A new information criterion is proposed by slightly adjusting the first‐order bias‐corrected AIC. Although the adjustment is achieved by merely using constant coefficients, the bias of the new criterion is reduced to $O(n^{-2})$ . Then, a variance of the new criterion is also improved. Through numerical experiments, we verify that our criterion is superior to others. The Canadian Journal of Statistics 39: 126–146; 2011 © 2011 Statistical Society of Canada     

Unauthorized Status and Youth Development in the United States: Consensus Statement of the Society for Research on Adolescence

In the United States, 5.3 million children and adolescents are growing up either with unauthorized status or with at least one parent who has that status. Until recently, little in the way of research has informed federal, state, and local policy debates related to unauthorized status (e.g., border enforcement, deportation, and a pathway to citizenship) although these issues have important implications for youth development. This statement is a brief summary of the research evidence on multiple domains of development that may be affected by the child or parent's unauthorized status. We also describe the contextual and psychological mechanisms that may link this status to developmental outcomes. We summarize a range of policies and practices that could reduce the developmental harm to children, youth, and their families stemming from this status. Finally, we conclude with recommendations for policy, practice, and research that are based on the evidence reviewed.     

Person‐Environment Fit and Positive Youth Development in the Context of High School Gay–Straight Alliances

Drawing from a person‐environment fit framework, we identified profiles of youth in gay–straight alliances (GSAs) based on the extent to which they received information/resources, socializing/support, and advocacy opportunities in their GSAs and the extent to which this matched what they desired from their GSA along these three functions. Further, we examined profile differences in positive developmental competencies while accounting for community‐contextual factors. In a sample of 290 youth from 42 Massachusetts GSAs, latent profile analyses identified five subgroups. Overall, youth receiving less from their GSAs than they desired, particularly regarding opportunities for advocacy, reported lower levels of self‐reflection, bravery, civic engagement, and agency than youth who received information, socializing/support, and advocacy that matched or exceeded what they desired.     

Parents' Goals for Children: The Dynamic Coexistence of Individualism and Collectivism in Cultures and Individuals

Current scholarship on the cultural value systems of individualism and collectivism, and the associated developmental goals of autonomy and relatedness, has moved beyond grand divide theories to emphasize variation within individuals and cultures. We present a theoretical model on the dynamic coexistence of cultural value systems (at the macro level) and parents' developmental goals (at the micro level). We contend that cultural values and developmental goals that have largely been classified as polar opposites may be viewed as conflicting, additive, or functionally dependent. Parents may view the developmental goal of autonomy as interfering with the goal of relatedness (and vice versa); parents may endorse both autonomy and relatedness; and parents may consider the developmental goal of relatedness to be a path to the goal of autonomy and/or autonomy to be a path to relatedness. These forms of coexistence are themselves dynamic, changing across situations, developmental time, and in response to social, political, and economic contexts.     

Aftershocks of Chile's earthquake for an ongoing, large-scale experimental evaluation

Evaluation designs for social programs are developed assuming minimal or no disruption from external shocks, such as natural disasters. This is because extremely rare shocks may not make it worthwhile to account for them in the design. Among extreme shocks is the 2010 Chile earthquake. Un Buen Comienzo (UBC), an ongoing early childhood program in Chile, was directly affected by the earthquake. This article discusses (a) the factors the UBC team considered for deciding whether to put on hold or continue implementation and data collection for this experimental study; and (b) how the team reached consensus on those decisions. A lesson learned is that the use of an experimental design for UBC insured that the evaluation's internal validity was not compromised by the earthquake's consequences, although cohort comparisons were compromised. Other lessons can be transferred to other contexts where external shocks affect an ongoing experimental or quasi-experimental impact evaluation.     

Predicting the timing of maternal employment after birth among a low-income and ethnically diverse sample

Policy pressures in the USA to transition parents from public assistance to work and concerns about the effects of early maternal employment on children highlight the importance of studying predictors of the timing of postpartum maternal employment. Little attention has been given to postpartum employment patterns of low-income ethnic minorities and immigrants, whose working conditions and employment prospects are different from white, middle-class mothers. Using a sample of low-income Mexicans, Dominicans, and African-Americans (N = 310), we studied whether and when mothers start working the first year following childbirth, and what factors promote or delay postpartum employment. Using discrete-time survival analysis, we modeled the odds of working at each month and tested the influence of family context, mothers' work and family values and plans, maternity leave benefit, and instrumental support availability on the timing of employment. By 11 months, half of the mothers had started working. Having maternity leave, plans to work, childcare arrangements, and a strong work orientation increased the odds of working. Household earnings were related to postpartum employment, but this effect varied over time. For African-Americans, instrumental support availability predicted earlier returns to employment, whereas for Mexicans and Dominicans it related to later returns to employment.