Assessing accuracy of a continuous screening test in the presence of verification bias

Summary.  In studies to assess the accuracy of a screening test, often definitive disease assessment is too invasive or expensive to be ascertained on all the study subjects. Although it may be more ethical or cost effective to ascertain the true disease status with a higher rate in study subjects where the screening test or additional information is suggestive of disease, estimates of accuracy can be biased in a study with such a design. This bias is known as verification bias. Verification bias correction methods that accommodate screening tests with binary or ordinal responses have been developed; however, no verification bias correction methods exist for tests with continuous results. We propose and compare imputation and reweighting bias-corrected estimators of true and false positive rates, receiver operating characteristic curves and area under the receiver operating characteristic curve for continuous tests. Distribution theory and simulation studies are used to compare the proposed estimators with respect to bias, relative efficiency and robustness to model misspecification. The bias correction estimators proposed are applied to data from a study of screening tests for neonatal hearing loss.     

Relational Health and Masculine Gender-Role Conflict in the Friendships and Community Relationships of Bisexual,Gay, and Straight Men

This study examined how men's masculine gender-role conflict and the importance men placed on interpersonal relationships in defining their self-identities predicted their relational health experiences in same-sex, dyadic friendships and community relationships. Using an Internet sample of 283 self-identified bisexual, gay, and straight men, results of hierarchical linear regression analyses indicated that for men across sexual orientations, the more importance men placed on interpersonal relationships with other men, the greater the degree of relational health they experienced in dyadic friendships. Additionally, for bisexual and gay men in dyadic friendships with other men, gender-role conflict was inversely related to the relational health of their friendships. In the domain of community relationships, the importance that bisexual and straight men placed on interpersonal relationships in defining their self-identities and levels of gender-role conflict predicted relational health experiences. For gay men, however, feelings of masculine gender-role conflict, alone, predicted poorer relational health in community relationships. Study limitations, clinical implications for practice, and future research directions are discussed.     

Analysing change in clinical trials using quasi-likelihoods

In clinical trials, investigations focus upon whether a treatment affects a measured outcome. Data often collected include pre- and post-treatment measurements on each patient and an analysis of the change in the outcome is typically performed to determine treatment efficacy. Absolute change and relative change are frequently selected as the outcome. In selecting from these two measures, the analyst makes implicit assumptions regarding the mean and variance-mean relationship of the data. Some have provided ad hoc guidelines for selecting between the two measures. We present a more rigorous means of investigating change using quasi-likelihoods. We show that both absolute change and relative change are special cases of the specified quasi-likelihood model. A cystic fibrosis example is provided.     

Identity Matters: A New Intervention Threshold for Social Work Practitioners Working with African American Adolescents

The aim of this study was to provide empirical evidence for the notion that social work interventionists should consider identity issues in African American adolescents as a foci in the development of intervention strategies. The author provides an overview of the major identity constructs and their interrelationships in African American adolescents. An example of the pervasiveness of relevant identity issues in African American adolescents was demonstrated by using a regression analysis to determine how identity characteristics predicted various forms of aggression in incarcerated and nonincarcerated youth. Significant statistical findings and theoretical support was used to sustain the rational of identity matters.     

Evaluating Risk Communication: Narrative vs. Technical Presentations of Information About Radon

This paper reports on an experiment to test the hypothesis that people respond better to risk communication that reflects more closely the conditions of their social and cultural lives. The experiment used the case of radon to determine whether technical or narrative forms of risk communication were more effective at drawing people's attention, imparting information, and modifying behavior. Two series of articles on radon were placed in the local newspapers of two Massachusetts communities. Homeowner attitudes, knowledge, and responses were monitored in baseline and follow-up telephone surveys. A third community was selected for comparison. The newspaper series were developed on the basis of previous research and six focus groups conducted with homeowners. The technical series presented authoritative, factual risk information, in the scientific style of the passive voice with generalized and impersonal language. The narrative series consisted of dramatized accounts of individuals making decisions about radon testing and mitigation, written in a more personal style. The findings from the focus groups confirm the results of previous studies, but the small size of the follow-up samples was a limiting factor in drawing definitive conclusions about the relative effectiveness of the two formats. The experiment demonstrates the difficulty of any risk communication effort on radon and underscores the need for good research design.(ABSTRACT TRUNCATED AT 250 WORDS)     

Measuring BSW Student Learning in Field Instruction

This study investigates whether undergraduate social work students deepen their professional foundation knowledge as a result of completing the field practicum and two additional social work foundation courses. The Area Concentration Achievement Test in Social Work (ACAT), which tests knowledge of the social work professional foundation, was administered to 70 students in the BSW program at the University of Texas-Pan American; 32 had nearly completed field instruction, and 38 were approved for field instruction but had not yet begun it. No differences were found between these groups related to performance on the overall ACAT or in four individual content areas. This counterintuitive finding challenges the assumption that knowledge deepens as students proceed through the curriculum and field instruction. Other variables that could affect performance on the ACAT are also explored.     

Love,Safety, and Companionship: The Human-Animal Bond and Latino Families

A survey found that 69.2% of a sample of 208 Latino university students in south Texas owned companion animals. Dogs were the most commonly owned companion animals, and 92% of dog and cat guardians regarded their companion animals as family members. Over 80% of the dog and cat guardians specified companionship and unconditional love as benefits offered by their animals. Eighty-six percent of dog guardians, compared to 44% of cat guardians, received a sense of safety from their animals. Assessment of the role of a companion animal in a family should guide a practitioner's decision about whether and how to include the animal in therapeutic interventions.     

Information fraction estimation: Strategies for a phase 3 non-inferiority maximum duration design with time to event outcome

There is considerable debate surrounding the choice of methods to estimate information fraction for futility monitoring in a randomized non-inferiority maximum duration trial. This question was motivated by a pediatric oncology study that aimed to establish non-inferiority for two primary outcomes. While non-inferiority was determined for one outcome, the futility monitoring of the other outcome failed to stop the trial early, despite accumulating evidence of inferiority. For a one-sided trial design for which the intervention is inferior to the standard therapy, futility monitoring should provide the opportunity to terminate the trial early. Our research focuses on the Total Control Only (TCO) method, which is defined as a ratio of observed events to total events exclusively within the standard treatment regimen. We investigate its properties in stopping a trial early in favor of inferiority. Simulation results comparing the TCO method with alternative methods, one based on the assumption of an inferior treatment effect (TH0), and the other based on a specified hypothesis of a non-inferior treatment effect (THA), were provided under various pediatric oncology trial design settings. The TCO method is the only method that provides unbiased information fraction estimates regardless of the hypothesis assumptions and exhibits a good power and a comparable type I error rate at each interim analysis compared to other methods. Although none of the methods is uniformly superior on all criteria, the TCO method possesses favorable characteristics, making it a compelling choice for estimating the information fraction when the aim is to reduce cancer treatment-related adverse outcomes.