Multiple Segment Factorial Vignette Designs

The multiple segment factorial vignette design (MSFV) combines elements of experimental designs and probability sampling with the inductive, exploratory approach of qualitative research. MSFVs allow researchers to investigate topics that may be hard to study because of ethical or logistical concerns. Participants are presented with short stories about hypothetical characters. These stories comprise 2 – 5 segments in which randomly assigned dimensions are introduced sequentially. Researchers control the occurrence and timing of when dimensions are presented. Respondents are asked questions after each segment. MSFVs may include written, oral, and visual stimuli. These efficient designs elicit quantitative data about causal relations and qualitative data within complex, multidimensional contexts. We discuss how to develop MSFV and suggest ways to avoid problems.     

Introduction: The Residential Context of Health

Our understanding of the relationship between housing and health will improve with closer attention to the characteristics of residents, their activities in relation to their housing, and social ecological factors that set the boundaries for those activities. To highlight these aspects of the subject area, we propose recharacterizing the housing and health field as one of inquiry into the residential context of health. In introducing this issue of the journal, we first elaborate on this proposal in conceptual and practical terms. We then overview the individual articles, each of which helps us develop a more nuanced view of the subject area. Finally, we comment on two themes running through multiple articles—stress and coping, and social ecological influences on residence .     

Determination of an Occupational Exposure Guideline for Manganese Using the Benchmark Method

An occupational risk assessment for manganese (Mn) was performed based on benchmark dose analysis of data from two epidemiological studies providing dose-response information regarding the potential neurological effects of exposure to airborne Mn below the current Occupational Safety and Health Administration (OSHA) Permissible Exposure Level (PEL) of 5 mg Mn/m3. Based on a review of the scientific evidence regarding the toxicity of Mn, it was determined that the most appropriate measure of exposure to airborne Mn for the subclinical effects measured in these studies is recent (rather than historical or cumulative) concentration of Mn in respirable (rather than total) particulate. For each of the studies analyzed, the individual exposure and response data from the original study had been made available by the investigators. From these two studies benchmark concentrations calculated for eight endpoints ranged from 0.09 to 0.27 mg Mn/m3. From our evaluation of these results, and considering the fact that the subtle, subclinical effects represented by the neurological endpoints tested in these studies do not represent material impairment, we believe an appropriate occupational exposure guideline for manganese would be in the range of 0.1 to 0.3 mg Mn/m3, based on the respirable particulate fraction only, and expressed as an 8-hour time-weighted average.     

Book Review: Mokhbul Morshed Ahmad,Understanding the South: How Northern Donor Agencies and NGOs Understand the Needs and Problems of Southern NGO Clients,Social Sciences Research Council,National University of Ireland,Galway, 2001, 244 pp., bibliography, $20.00

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations -