Estimation and diagnostic for skew-normal partially linear models

Partially linear models (PLMs) are an important tool in modelling economic and biometric data and are considered as a flexible generalization of the linear model by including a nonparametric component of some covariate into the linear predictor. Usually, the error component is assumed to follow a normal distribution. However, the theory and application (through simulation or experimentation) often generate a great amount of data sets that are skewed. The objective of this paper is to extend the PLMs allowing the errors to follow a skew-normal distribution [A. Azzalini, A class of distributions which includes the normal ones, Scand. J. Statist. 12 (1985), pp. 171–178], increasing the flexibility of the model. In particular, we develop the expectation-maximization (EM) algorithm for linear regression models and diagnostic analysis via local influence as well as generalized leverage, following [H. Zhu and S. Lee, Local influence for incomplete-data models, J. R. Stat. Soc. Ser. B 63 (2001), pp. 111–126]. A simulation study is also conducted to evaluate the efficiency of the EM algorithm. Finally, a suitable transformation is applied in a data set on ragweed pollen concentration in order to fit PLMs under asymmetric distributions. An illustrative comparison is performed between normal and skew-normal errors.     

Asymmetrically fair rules for an indivisible good problem with a budget constraint

We study a particular restitution problem where there is an indivisible good (land or property) over which two agents have rights: the dispossessed agent and the owner. A third party, possibly the government, seeks to resolve the situation by assigning rights to one and compensate the other. There is also a maximum amount of money available for the compensation. We characterize a family of asymmetrically fair rules that are immune to strategic behavior, guarantee minimal welfare levels for the agents, and satisfy the budget constraint.     

Conditional moving linear regression: Modeling the recruitment process for ALLHAT

Effective recruitment is a prerequisite for successful execution of a clinical trial. ALLHAT, a large hypertension treatment trial (N = 42,418), provided an opportunity to evaluate adaptive modeling of recruitment processes using conditional moving linear regression. Our statistical modeling of recruitment, comparing Brownian and fractional Brownian motion, indicates that fractional Brownian motion combined with moving linear regression is better than classic Brownian motion in terms of higher conditional probability of achieving a global recruitment goal in 4-week ahead projections. Further research is needed to evaluate how recruitment modeling can assist clinical trialists in planning and executing clinical trials.     

A further examination of antecedents of correctional staff life satisfaction

Working in corrections is not only a demanding job, but a socially important one. While a growing number of studies have examined how the work environment impacts the job stress, job satisfaction, and organizational commitment of staff, very few studies have examined how working in corrections impacts the life satisfaction of workers. The current study utilized OLS regression to examine the antecedents of life satisfaction among staff at a Midwestern private prison. Job satisfaction had a positive relationship with life satisfaction, while age, work on family conflict, family on work conflict, and job involvement all had statistically significant negative effects. Finally, perceptions of the level of financial rewards, job stress, organizational commitment, gender, race, educational level, tenure, supervisory status, position, marital status, and having children, all had non-significant associations with overall satisfaction with life.     

The Social Structuring of Mental Health over the Adult Life Course: Advancing Theory in the Sociology of Aging

The sociology of aging draws on a broad array of theoretical perspectives from several disciplines, but rarely has it developed its own. We build on past work to advance and empirically test a model of mental health framed in terms of structural theorizing and situated within the life course perspective. Whereas most prior research has been based on cross-sectional data, we utilize four waves of data from a nationally representative sample of American adults (Americans' Changing Lives Study) collected prospectively over a 15-year period and find that education, employment and marital status, as well as their consequences for income and health, effectively explain the increase in depressive symptoms after age 65. We also found significant cohort differences in age trajectories of mental health that were partly explained by historical increases in education. We demonstrate that a purely structural theory can take us far in explaining later life mental health.     

The Influence of Union Instability and Union Quality on Children's Aggressive Behavior

We investigate whether mother's poor union quality attenuates the association between union instability and young children's behavioral adjustment. Using data from three waves of the Fragile Families and Child Wellbeing Study to consider children born to married or cohabiting mothers (N=1,730), we determine that children who have experienced poor union quality between mothers and their partners have higher predicted aggressive behavior scores at age 3, regardless of whether they have experienced union transitions, compared to children who have experienced high-quality, stable unions. Children who have experienced instability in the context of higher-quality unions and relatively less acrimonious dissolutions are similar to children raised in high-quality stable unions in terms of predicted aggressive behavior scores.     

Psychopathology in pathological gamblers seeking treatment

High rates of psychiatric symptoms have been reported in pathological gamblers. This study of psychiatric comorbidity in pathological gamblers is the first to use structured psychiatric interviews assessing DSM-III-R Axis I and II disorders. The Structured Clinical Interview for DSM III-R (SCID-P, SCID-II) was administered to 40 (25 male, 15 male) pathological gamblers seeking outpatient treatment in Minnesota for gambling, and 64 (41 male, 23 female) controls. High lifetime rates of Axis I (92%) but not Axis II (25%) psychopathology were found in pathological gamblers as compared to controls. No differences between male and female gamblers were found in rates of affective, substance use or personality disorders. Females had higher rates of anxiety disorders and histories of physical/sexual abuse. Possible associations between psychiatric disorders and pathological gambling are discussed along with gambler typologies and implications for future research.The authors wish to gratefully acknowledge the assistance of: Gary Christenson, M.D., Carol Peterson, Ph.D., William Meller, M.D., Thomas Mackenzie, M.D.     

The child welfare response to serious nonaccidental head trauma

Serious nonaccidental head trauma (NHT) can leave permanent neurological damage in children who survive abuse. This study reports on child welfare's handling of NHT cases compared with cases of physical abuse and head trauma due to neglect with regard to placement in foster care, reunification with family, and safety issues. The results show that workers placed children with NHT in foster care immediately after the abuse but treated them no differently than other physically abused children regarding reunification.     

Improving access to health care for foster children: the Illinois model

Children in foster care have lower health status than do their peers and limited access to health care. The Illinois Department of Children and Family Services developed HealthWorks, a separate primary care preferred provider system for children in foster care. This study compared claims data for children in HealthWorks with children not enrolled in HealthWorks and with children in Aid to Families with Dependent Children (AFDC) who had never entered foster care. Children enrolled in HealthWorks were more likely than were other children to receive all of the services except general inpatient hospitalizations. They had greater odds of receiving general exams and physicians' services and were more likely to visit the emergency room than children who were not enrolled. They were more likely to receive all of the measured services when compared with children receiving Medicaid through AFDC.