RESIDENTIAL MOBILITY AND ATTEMPTED SUICIDE AMONG ADOLESCENTS: An Individual-Level Analysis

Building on the Durkheimian legacy's emphasis on social integration as a determinant of suicidal behavior, many macrolevel studies have observed an association between aggregate rates of geographical mobility and suicide, but little research has explored this connection at the individual level. We use data from 9,594 respondents who participated in two waves of the National Longitudinal Study of Adolescent Health to examine the effect of recent residential mobility on attempted suicide one year later and to explore the mechanisms that potentially transmit this effect. We find that among adolescent girls, recent movers are about 60 percent more likely than nonmovers to report having attempted suicide during the following year and that this difference cannot be readily explained by mover versus nonmover differences in preexisting demographic and family background characteristics. Some of the apparent effect of residential mobility on females' risk of attempting suicide operates through higher rates of victimization and delinquency, lower levels of school attachment, higher rates of social isolation, and a tendency for movers to associate with peers who exhibit delinquent behaviors and who themselves have attempted suicide. In contrast, we find no evidence that mobile female adolescents' deficit of parental social capital or lower levels of school engagement can account for the difference in attempted suicide risk between movers and nonmovers. We also find that residential mobility is not significantly associated with suicide attempts among adolescent males.     

Optimally robust credible sets with a class of priors

We determine a credible set A   that is the “best” with respect to the variation of the prior distribution in a neighborhood Γ$\Gamma$ of the starting prior _π0(θ)${\pi }_0(\theta )$. Among the class of sets with credibility γ$\gamma$ under _π0${\pi }_0$, the “optimally robust” set will be the one which maximizes the minimum probability of including θ$\theta$ as the prior varies over Γ$\Gamma$. This procedure is also Γ-minimax$\Gamma \text{-minimax}$ with respect to the risk function, probability of non-inclusion. We find the optimally robust credible set for three neighborhood classes Γ$\Gamma$, the ε-contamination$\epsilon \text{-contamination}$ class, the density ratio class and the density bounded class. A consequence of this investigation is that the maximum likelihood set is seen to be an optimal credible set from a robustness perspective.     

Balanced e-optimal designs of resolution III for the 2×3 series

We consider the problem of constructing designs which are E-optimal in the class of all balanced resolution III designs for the 2^m×3ⁿ series. The inverse of the information matrix for general resolution III balanced 2^m×3ⁿ designs is obtained. Optimal designs are constructed for the cases (m,n)=(3, 1), (4, 1), (2, 2) and (3, 2) for various numbers of runs in the practical range.     

Richness orderings

An index of richness in a society is a measure of the extent of its affluence. This paper presents an analytical discussion on several indices of richness and their properties. It also develops criteria for ordering alternative distributions of income in terms of their richness. Given a line of richness, an income level above which a person is regarded as rich, and depending on the redistributive principle, it is shown that the ranking relation can be implemented by seeking dominance with respect to the generalized Lorenz curve of the rich or the affluence profile of the society. When the line of richness is assumed to be variable, we need to employ the stochastic dominance conditions for ordering the income distributions.     

Residential mobility and the onset of adolescent sexual activity

Data from almost 5,000 adolescent respondents to the National Longitudinal Study of Adolescent Health (Add Health) are used to examine the mechanisms that transmit the facilitative effect of residential mobility on the timing of the transition to first premarital sexual intercourse. Adolescents who have recently moved are approximately one third more likely than nonmobile adolescents to experience first premarital intercourse between the first two waves of Add Health. We find that much of the difference between adolescent movers and stayers in the onset of sexual activity is attributable to the greater propensity for delinquency and the weaker academic performance among members of movers’ school‐based friendship networks. Adolescents’ own delinquent behavior and academic performance also help to mediate the association between residential mobility and the transition to first intercourse.     

Modeling Bimodal Discrete Data Using Conway-Maxwell-Poisson Mixture Models

Bimodal truncated count distributions are frequently observed in aggregate survey data and in user ratings when respondents are mixed in their opinion. They also arise in censored count data, where the highest category might create an additional mode. Modeling bimodal behavior in discrete data is useful for various purposes, from comparing shapes of different samples (or survey questions) to predicting future ratings by new raters. The Poisson distribution is the most common distribution for fitting count data and can be modified to achieve mixtures of truncated Poisson distributions. However, it is suitable only for modeling equidispersed distributions and is limited in its ability to capture bimodality. The Conway–Maxwell–Poisson (CMP) distribution is a two-parameter generalization of the Poisson distribution that allows for over- and underdispersion. In this work, we propose a mixture of CMPs for capturing a wide range of truncated discrete data, which can exhibit unimodal and bimodal behavior. We present methods for estimating the parameters of a mixture of two CMP distributions using an EM approach. Our approach introduces a special two-step optimization within the M step to estimate multiple parameters. We examine computational and theoretical issues. The methods are illustrated for modeling ordered rating data as well as truncated count data, using simulated and real examples.     

Admissibility in factorial designs

The notion of admissibility in factorial designs has been introduced. It has been shown that factorial designs which are binary and have a C-matrix with property A are admissible.     

Pfeifer records process

In this article, we study the limit distribution of sums of Pfeifer records. Motivated by the results obtained by Arnold and Villaseñor [Generalized order statistics process and Pfeifer records, Statistics 46(3) (2012), pp. 373–385], we show that the partial sum process of Pfeifer records converge to a function of the Brownian motion. The normalization is either a sequence of appropriate constants or a sequence of functions, depending on the tail behaviour of the underlying variables. These results, in particular, prove stronger version of results obtained in Villaseñor and Arnold [On limit laws for sums of Pfeifer records, Extremes 10 (2007), pp. 235–248] and Bose and Gangopadhyay [Convergence of linear functions of Pfeifer records, Extremes 13 (2010), pp. 89–106] and extends results of Bose et al. [Partial sum process for records, Extremes 8 (2005), pp. 43–56] from classical records to Pfeifer records.     

A law of large numbers for the scaled age distribution of linear birth-and-death processes

It is shown that certain measure-valued stochastic processes describing the age distribution of particles whose development is controlled by linear critical birth-and-death processes converge in distribution to a deterministic positive bounded measure.