Modeling Longitudinal Obesity Data with Intermittent Missingness Using a New Latent Variable Model

We propose a latent variable model for informative missingness in longitudinal studies which is an extension of latent dropout class model. In our model, the value of the latent variable is affected by the missingness pattern and it is also used as a covariate in modeling the longitudinal response. So the latent variable links the longitudinal response and the missingness process. In our model, the latent variable is continuous instead of categorical and we assume that it is from a normal distribution. The EM algorithm is used to obtain the estimates of the parameter we are interested in and Gauss–Hermite quadrature is used to approximate the integration of the latent variable. The standard errors of the parameter estimates can be obtained from the bootstrap method or from the inverse of the Fisher information matrix of the final marginal likelihood. Comparisons are made to the mixed model and complete-case analysis in terms of a clinical trial dataset, which is Weight Gain Prevention among Women (WGPW) study. We use the generalized Pearson residuals to assess the fit of the proposed latent variable model.     

Identifying and Troubleshooting Link-Resolution Issues with ILL Data

Troubleshooting when a link resolver goes wrong can be difficult as it usually relies on the user to report the problem. Using data on interlibrary loan requests that have been cancelled because the materials are available online is one way that libraries can examine where link resolvers may be failing. For the 2012/2013 school year, the Samford University Library looked at this cancelled interlibrary loan request data to determine where their new link resolver and knowledgebase needed further customization to improve the user experience. This process not only identified a number of problems all along the link resolution chain, but it also put in place an ongoing process for identifying and troubleshooting link resolution issues in the future.     

In-vehicle fatalities,seat belts,and compulsory seat belt legislation: The Manitoba experience

Using medical data from the Medical Officer of Health (MOH) the paper presents an exploratory mutivariate statistical analysis of in-vehicle mortality in Manitoba, 1983–85. It is found that total mortality had increased in excess of 31% following the introduction of compulsory seat-belt legislation in April, 1984. It is also found that in-vehicle mortality is related to average age of drivers/occupants, sex of victims, blood alcohol level, and in some cases seat-belt use. Since the data represents a chronological series it is not possible to disentangle the physical effect of seat-belts and the compulsory seat-belt legislation.     

Daughter‐Father Relationships and Adolescent Psychosocial Functioning in Low‐Income African American Families

This study examines the role of biological and social fathers in the lives of low‐income African American adolescent girls (N= 302). Sixty‐five percent of adolescents identified a primary father; two thirds were biological and one third were social fathers. Adolescents reported more contentious and less close relationships with biological than with social fathers. Multivariate regression analyses indicated that daughters' perceptions of anger and alienation from fathers was related to greater emotional and behavioral problems for adolescents, whereas perceptions of trust and communication with fathers were not predictive of youth outcomes. These relationships were generally similar for biological and social fathers, but differed according to fathers' level of contact with their daughters. A combination of low contact and high levels of either anger or trust in the daughter‐father relationship related to particularly deleterious psychosocial outcomes for adolescent girls.     

Reducing transfers of children in family foster care through onsite mental health interventions

This article describes a successful pilot project in New York City that effectively reduced the number of transfers or replacements of children in family foster care through the placement of mental health clinicians onsite at two foster care agencies.