Simultaneous estimation of gamma means using a hierarchical generalized linear model

The problem of simultaneously estimating p Gamma means is investigated when the means are believed a priori to satisfy an r-dimensional generalized linear model. Using a Bayesian hierarchical model to reflect the uncertainty in the linear model, approximate methods are proposed to compute the posterior densities. The resulting estimator shrinks the usual estimator toward a prior estimator where the size of the shrinkage depends upon the agreement of the observed data with the proposed generalized linear model.     

Web-based triage in a college health setting

The authors describe the initiation and use of a Web-based triage system in a college health setting. During the first 4 months of implementation, the system recorded 1,290 encounters. More women accessed the system (70%); the average age was 21.8 years. The Web-based triage system advised the majority of students to seek care within 24 hours; however, it recommended self-care management in 22.7% of encounters. Sore throat was the most frequent chief complaint (14.2%). A subset of 59 students received treatment at student health services after requesting an appointment via e-mail. The authors used kappa statistics to compare congruence between chief complaint and 24/7 WebMed classification (kappa = .94), between chief complaint and student health center diagnosis (kappa = .91), and between 24/7 WebMed classification and student health center diagnosis (kappa = .89). Initial evaluation showed high use and good accuracy of Web-based triage. This service provides education and advice to students about their health care concerns.     

Cameras and community health

Photography projects are an alternative teaching method that can be easily integrated into community programs with adolescents and children. This article provides a brief review of the use of photography in documenting social and health issues. Two examples of community photography projects with easily ignored populations are described. These projects gave a voice to participants and allowed them to demonstrate their creativity with cameras. An implementation guide is presented to provide concrete suggestions for implementing community photography projects.     

Reliability of translated measures assessing dating violence among Mexican adolescents

Research on the prevalence and correlates of dating violence in Mexican teens is challenged by the lack of culturally and linguistically appropriate assessment tools. This study modified, translated, and back-translated the Conflict in Adolescent Dating Relationships Inventory (CADRI; Wolfe et al., 2001) and the Attitudes Towards Dating Violence Scales (Price, Byers, & the Dating Violence Research Team, 1999) for Mexican adolescents. Analyses on 307 adolescents (15-18 years old) from Monterrey and Mexicali, Mexico, revealed that most of the translated CADRI subscales and Attitudes Towards Dating Violence Scales had acceptable internal consistency and test-retest reliability coefficients. The study offers some evidence that the measures may be useful in assessing dating violence in Mexican teens.     

Mexican/Mexican American Adolescents and keepin' it REAL: An Evidence-Based Substance Use Prevention Program

A randomized trial tested the efficacy of three curriculum versions teaching drug resistance strategies, one modeled on Mexican American culture; another modeled on European American and African American culture; and a multicultural version. Self-report data at baseline and 14 months post-intervention were obtained from 3, 402 Mexican heritage students in 35 Arizona middle schools, including 11 control sites. Tests for intervention effects used simultaneous regression models, multiple imputation of missing data, and adjustments for random effects. Compared with controls, students in the Latino version reported less overall substance use and marijuana use, stronger intentions to refuse substances, greater confidence they could do so, and lower estimates of substance-using peers. Students in the multicultural version reported less alcohol, marijuana, and overall substance use. Although program effects were confined to the Latino and multicultural versions, tests of their relative efficacy compared with the non-Latino version found no significant differences. Implications for evidence-based practice and prevention program designs are discussed, including the role of school social workers in culturally grounded prevention.     

Robust multivariate analysis of variability

A general testing procedure is proposed to multivariately test for equality of p variances among k groups. The procedure applies a multivariate analysis of variance on an appropriate measure of spread for the uncensored original observations. Three such measures of spread are compared in a simulation experiment which considered two and three variables with equal and unequal sample sizes for the null and alternative hypotheses for Gaussian, Student's t (8, 12, and 20 degrees of freedom) and gamma (α=2,4,6 and 10) distributions . The likelihood ratio test (Box, 1949) was included in the above simulations. The results suggest that if one chooses a measure of spread appropriate for the distribution of the original observations, the proposed MANOVA-based testing procedure is robust and reasonably powerful. Using this procedure for the normal distribution, similar power was observed to that of the likelihood ratio test when the variables were uncorrelated or had little positive correlation.     

Analysis of incomplete data under non-random mechanisms: bayesian inference

Inferences are made concerning population proportions when data are not missing at random.Both one sample and two sample situations are considered with examples in clinical trials.The one samplesituation involves the existence of response related incomplete data in a study conducted to make inferences involving the proportion. The two sample problem involves comparing two treatments in clinical trials when there exists dropouts due to both the treatment and the response to the treatment.Bayes procedures are used in estimating parameters of interest and testing hypotheses of interest in these two situations. An ad-hoc approach to the classical inference is presented for each ofthe two situations and compared with the Bayesian approach discussed. To illustrate the theory developed, data from clinical trials of severe head trauma patients at the Medical College of Virginia Head Injury Center from 1984 to 1987 is considered     

Is migration an effective adaptation to climate-related agricultural distress in sub-Saharan Africa?

Population and Environment - Migration is often considered a form of climate change adaptation by which individuals, households, and communities seek to reduce the risks associated with climate...