Small Sample Tests for Shape Parameters of Gamma Distributions

The introduction of shape parameters into statistical distributions provided flexible models that produced better fit to experimental data. The Weibull and gamma families are prime examples wherein shape parameters produce more reliable statistical models than standard exponential models in lifetime studies. In the presence of many independent gamma populations, one may test equality (or homogeneity) of shape parameters. In this article, we develop two tests for testing shape parameters of gamma distributions using chi-square distributions, stochastic majorization, and Schur convexity. The first one tests hypotheses on the shape parameter of a single gamma distribution. We numerically examine the performance of this test and find that it controls Type I error rate for small samples. To compare shape parameters of a set of independent gamma populations, we develop a test that is unbiased in the sense of Schur convexity. These tests are motivated by the need to have simple, easy to use tests and accurate procedures in case of small samples. We illustrate the new tests using three real datasets taken from engineering and environmental science. In addition, we investigate the Bayes’ factor in this context and conclude that for small samples, the frequentist approach performs better than the Bayesian approach.     

Mechanisms of Family Impact on African American Adolescents' HIV‐Related Behavior

A longitudinal model that tested mediating pathways between protective family processes and HIV‐related behavior was evaluated with 195 African American youth. Three waves of data were collected when the youth were 13, 15, and 19 years old. Evidence of mediation and temporal priority were assessed for 3 constructs: academic engagement, evaluations of prototypical risk‐taking peers, and affiliations with risk‐promoting peers. Structural equation modeling indicated that protective family processes assessed during early adolescence were associated with HIV‐related behavior during emerging adulthood and that academic engagement, evaluations of prototypical risk‐taking peers, and affiliations with risk‐promoting peers accounted for this association. Evidence of a specific pathway emerged: protective family processes→academic engagement→negative evaluations of prototypical risk‐taking peers→affiliations with risk‐promoting peers→HIV‐related behavior. Academic engagement also was a direct predictor of HIV‐related risk behavior.     

Parental Involvement Promotes Rural African American Youths’ Self‐Pride and Sexual Self‐Concepts

This study, an evaluation of the Strong African American Families Program, was designed to determine whether intervention‐induced changes in targeted parenting behaviors were associated with young adolescents’ development of racial pride, self‐esteem, and sexual identity. Participants were 332 African American mothers and their 11‐year‐old children in 9 rural Georgia counties. Families were randomly assigned to a control group or an intervention group. Unlike those in the control families, mothers in the intervention group reported increases in targeted parenting behaviors, which promoted self‐esteem, positive racial identity, and positive sexual self‐concepts among their children. These findings expand the study of African American youths’ identity development by including broader domains of identity and parenting processes other than racial socialization.     

Using Personal Quality Assessment for Selection of Social Work Students

Abstract

The social work profession has long struggled to find fair and effective ways of selecting students into their education programs. A psychometric test battery, gathered together under the title “Personal Qualities Assessment” (PQA) has been developed at the University of Newcastle to identify a range of qualities in aspiring health professionals. Two of its components were used to determine whether there was a relationship between scores obtained by social work students in these tests and scores achieved in an empathic listening and critical review hurdle assessment prior to the first field placement. The results showed that social work students who were moderately empathic, not narcissistic, and moderately libertarian in their moral orientation performed better on the assessment than students who were less empathic, more narcissistic, or extreme in their moral orientation. These results suggest that measurement of these qualities could be useful in selecting the most suitable individuals for social work programs.     

There are no Answers,Only Choices: Teaching Ethical Decision Making in Social Work

Abstract

In teaching students about ethical decision making in social work, it is essential that the students are able to recognise the moral implications of their work and develop a deep understanding about ethical issues and their personal responsibility for making ethical choices. Thus, more than a “how to do it” approach is needed and teaching students about values and ethics is an essential thread that runs through our experience-based social work education program. The present paper describes a learning unit that sought to teach students about ethical decision making as a critical thinking process and, in so doing, to integrate students’ knowledge and experience of values, ethics, policy, and research in the final year of study. The relationship between values, ethics, policy, research, and social work practice provided an ideal context within which students could learn to integrate their knowledge and experience and apply it directly to their fieldwork practice. The paper ends with our critical reflection on this teaching experience and a critique of decisionist ethical frameworks.     

Designing Referral Network Structures and Decision Rules to Streamline Provision of Urgent Health and Human Services*

This study uses fully factorial computer simulation to identify referral network attributes and referral decision rules that streamline the routing of people to urgent, limited services. As an example of a scenario, the model represents vaccine delivery in a city of 100,000 people during the first 30 days of a pandemic. By modeling patterns of communication among health care providers and daily routing of overflow clients to affiliated organizations, the simulations determine cumulative effects of referral network designs and decision rules on citywide delivery of available vaccines. Referral networks generally improve delivery rates when compared with random local search by clients. Increasing the health care organizations’ tendencies to form referral partnerships from zero to about four partners per organization sharply increases vaccine delivery under most conditions, but further increases in partnering yield little or no gain in system performance. When making referrals, probabilistic selection among partner organizations that have any capacity to deliver vaccines is more effective than selection of the highest‐capacity partner, except when tendencies to form partnerships are very low. Implications for designing health and human service referral networks and helping practitioners optimize their use of the networks are discussed. Suggestions for using simulations to model comparable systems are provided.     

Vocational rehabilitation in multiple sclerosis (MS): a profile of clients seeking services

Although a number of innovative vocational rehabilitation (VR) demonstration projects have been completed with MS populations, there remains a lack of clarity as to a profile of these VR participants. An effort is made in this article to carefully describe the demographic and occupational characteristics of people with MS seeking vocational services at intake, as well as their self-perceived psychosocial functioning across a range of pertinent measures. The issue of "program dropouts" in VR services for people with MS is also addressed. Implications for better understanding participants with MS within the VR process and improved nuances in service delivery are then discussed.     

Ethical dilemmas in social research: no easy solutions

Correspondence to Bernard Gallagher, Research Fellow, Department of Social Policy and Social Work, University of Manchester, Dover St., Mancester M13 9PL. Summary Ethical dilemmas have been encountered in many areas of socialresearch and have at times been the subject of much controversy.Despite this, the problem of how to tackle ethical dilemmashas received little attention in the literature. As a result,researchers faced with these dilemmas have little knowledgeto draw upon, and groups associated with research, such as participatingagencies and ethics committees, may not fully appreciate allthe issues involved in dealing with ethical dilemmas. Theseissues are not only philosophical in nature but relate alsoto the methodological and practical implications of followingone, rather than another, ethical principle. The researchersencountered a number of ethical dilemmas in their research inchild protection. By discussing different approaches to solvingethical dilemmas, they intend to show that this is a complexproblem and one which, along with ethics in general, requiresgreater attention in the literature.