How does the DerSimonian and Laird procedure for random effects meta-analysis compare with its more efficient but harder to compute counterparts?

The procedure suggested by DerSimonian and Laird is the simplest and most commonly used method for fitting the random effects model for meta-analysis. Here it is shown that, unless all studies are of similar size, this is inefficient when estimating the between-study variance, but is remarkably efficient when estimating the treatment effect. If formal inference is restricted to statements about the treatment effect, and the sample size is large, there is little point in implementing more sophisticated methodology. However, it is further demonstrated, for a simple special case, that use of the profile likelihood results in actual coverage probabilities for 95% confidence intervals that are closer to nominal levels for smaller sample sizes. Alternative methods for making inferences for the treatment effect may therefore be preferable if the sample size is small, but the DerSimonian and Laird procedure retains its usefulness for larger samples.     

Probabilistic Applications of the Schlömilch Transformation

The Schlömilch transformation, long used by mathematicians for integral evaluation, allows probability mass to be redistributed, thus transforming old distributions to new ones. The transformation is used to introduce some new families of distributions on ⁺. Their general properties are studied, i.e., distributional shape and skewness, moments and inverse moments, hazard function, and random number generation. In general, these distributions are suitable for modeling data where the hazard function initially rises steeply. Their usefulness is illustrated by fitting some human weight data. Besides data fitting, one possible use of the new distributions could be in sensitivity or robustness studies, for example as Bayesian prior distributions.     

Barriers to evidence based practice in accommodations for an aging workforce

According to a recent Government Accountability Office report, the number of workers over age 55 is projected to increase significantly over the next twenty years, with this demographic group projected to comprise as much as twenty percent of the workforce by 2015 [12]. Accommodating the functional limitations of a large number of older workers may prove challenging for employers; however, policies and practices shaped over the course of the next few decades could allow aging workers to remain a valuable part of the US economy. Given these considerations, it is useful from a public policy perspective to determine the degree to which employers are currently addressing the accommodation needs of older workers. This paper presents the results of a study that attempted to determine the extent to which a sample of Fortune 500 employers was currently accommodating older workers. The study's methodology (in particular, its use of semi-structured telephone interviews) is reevaluated and new options (such as anonymous online employer surveys) are considered for the valid and reliable collection of data on accommodations for older workers.     

Work stressors and cardiovascular disease

Over the past 20 years, an extensive body of research evidence has documented that psychosocial work stressors are risk factors for hypertension and cardiovascular disease. These stressors, which appear to be increasing in prevalence, include job strain (the combination of psychological job demands and low job control), imbalance between job efforts and rewards, threat-avoidant vigilant work, and long work hours. This article reviews the evidence linking these stressors with hypertension and CVD, and the physiological and social psychological mechanisms underlying the associations. Also described are methods for measuring work stressors and new, more accurate techniques for measuring blood pressure. Finally, strategies for reducing work stressors and preventing hypertension and CVD are reviewed. These include clinical assessment, worksite health promotion, work organization interventions, legal approaches and work site surveillance.     

Data-Based Modeling of the Failure Rate of Repairable Equipment

A databaseof failures of many types of medical equipment was analysed,to study the dependence of failure rate on equipment age andon time since repair. The intention was to use this large datasetto assess the validity of some widely-used models of failurerate, such as the power-law and loglinear Poisson processes,and so to recommend simple and adequate models to those practitionershaving little data to discriminate between rival models. Theaim is also to illustrate a methodology for computing policycosts from failure databases. The power-law process model wasfound to fit slightly better overall than did the loglinear andlinear processes. Some related models were created to fit anobserved peaking of failure rate. The data showed a decreasinghazard of (first) failure after repair for some equipment types.This can be due to imperfect or hazardous repair, and also todiffering failure rates among a population of machines. Two simplemodels of imperfect repair were used to fit the data, and anEmpirical Bayes method was used to fit a model of variable failurerate between machines. Neglect of such variation can lead toan over-estimate of the hazardousness of repair.     

The effect of Video Display Terminal (VDT) mouse use on muscle contractions in the neck and forearm

This study used surface electromyography (EMG) to examine the percent of maximum voluntary contraction (%MVC) of the upper trapezius, the flexors of the wrist/fingers and extensors of the wrist/fingers during Video Display Terminal (VDT) mouse use with the mouse positioned either next to the computer or on a lapdesk. Thirty participants, between the ages of 18 and 40, used a VDT mouse to follow a prescribed pattern for three trials at each location. Although there was a trend towards the lapdesk location producing lower %MVC than the computer location for the trapezius and wrist/finger flexors (lapdesk: trapezius M 4.71%, wrist/finger flexors M 3.53%; computer: trapezius M 5.74%, wrist/finger flexors M 3.94%) a two way ANOVA controlling for sequence and order found no significant difference between the means. There was no trend for the effects of location for the wrist/finger extensors. These results suggest that changing the position of the mouse may not significantly reduce muscle contractions.     

The nature of working in the United States: an occupational therapy perspective

Although working is considered by occupational therapy practitioners to be an important life role, there is very little information about the nature of working in the occupational therapy literature. This article reviews the construct of working in three ways: 1) The history of working and how it has shaped the modern beliefs about working; 2) The nature of working; and 3) The health promoting attributes of working. The paper will also discuss research done on how working is viewed by individuals with disabilities and will touch on some of the implications of the cultural bias in the workplace toward workers with disabilities. Through this increased knowledge of the nature of working, occupational therapy practitioners and other vocational rehabilitation professionals will be better equipped to break down the subtle cultural barriers, and help individuals with disabilities to participate in working.     

The Real Controversy About Child Sexual Abuse ResearchContradictory Findings and Critical Issues Not Addressed by Rind, Tromovitch, and Bauserman in Their 1998 Outcomes Meta-Analysis

This article presents a review of all types of child sexual abuse research ignored by Rind, Tromovitch, and Bauserman in their 1998 meta-analytic study. Eight major findings are addressed. Altogether, these findings demonstrate the narrow focus of the Rind et al. meta-analysis. By restricting a supposedly broad meta-analysis to only some of the research and population in question, the conclusions Rind et al. drew regarding this complex topic (primarily, that adult-child sex is not necessarily harmful to children) are invalid.