From the Editors

Abstract

Yacov Haimes, our engineering area editor, begins the issue with his Perspective article that points out the proliferation of definitions of risk and the confusion created by these definitions. Professor Haimes suggests a definition grounded in systems theory and illustrates it with several examples. Consistent with the systems theory theme, seven of the ten research papers in this issue are efforts to understand a complex system through modeling its elements and their interactions with each other and external inputs. For example, noting the recent case of three missing mice that had been infected with the bacterium that causes plague, David Durham and Elizabeth Casman present a mathematical model that considers conditions that would increase the likelihood that the etiologic agent of plague can become established in an urban rat population. Area editor Tony Cox reviews a paper that used regression analysis to show a relationship between livestock operations and infant mortality. After reviewing the limitations of regression-based models, he emphasizes the advantages of using quantitative risk assessment (QRA), including emissions release (source) models, fate and transport modeling, exposure assessment, and dose-response modeling in order to avoid potentially misleading results. After noting the increasing use of recycled water, Margaret Donald et al. estimate potential health risks associated with water reuse. With gastroenteritis as the outcome, they build a model of the pathways, using expert opinion to provide some of the key assumptions. Greg Hood and Barry Simon discuss stochastic scenario trees as a way of looking for pests, weeds and diseases. They focus on the complexity of following all the trees created by the process. The authors conclude that many of the branches have identical outcomes and are therefore redundant, making the exercise more feasible in many cases. Funded by companies that produce vinyl chloride (VC) or vinyl-chloride containing products, Jennifer Sahmel et al. examine the exposure of hairdressers to vinyl chloride in hairspray during the 1960s and 1970s. By constructing models that allow them to study the drift of the substance, they model exposure in small, medium, and large salons. Using the assumption that all hairsprays used in a salon contained VC, they estimate the 95th percentile of the theoretical lifetime cumulative dose to be below the threshold dose for hepatic angiosarcoma published in the epidemiology literature. Roberta Grant et al. introduce an updated data set about the carcinogenicity of 1,3-Butadiene. The paper presents new exposure data, epidemiological observations, and modeling of these data. The last of the modeling papers, by Joost Santos and Mark Orsi, reviews the potential economic impacts of a serious pandemic in the United States. Using a dynamic version of an input-output model, they study the economic consequences of a reduced workforce in the State of Virginia. The other three papers in this issue deal with understanding how people respond to plausible risks. The Dutch are well-known for experiencing floods and for expertise in preventing flooding. Ruud Zaalberg et al. surveyed 516 individuals to identify factors that may motivate people to cope with flooding. Results show that that flood victims report strong emotions and social support due to past flooding, and they worry more than those with no flooding experiences about their vulnerability in future flooding. Ka Lok Lee, et al. study internet usage with a dataset of hourly web-surfing behavior of over 140,000 internet users in five southeastern states impacted by Hurricane Katrina in August of 2005. While observing more web traffic in places closer to the storm, they find that residents of Florida counties that had been most directly affected by Hurricane Dennis a month earlier displayed the most active responses and other interesting behavioral responses. Jooyoung Kim and Hye-Jin Paek visit the issue of pubic reaction to genetically modified foods, a topic frequently represented in this journal. The authors try to understand how people process messages, and how they react to efforts to change their perceptions. Their sample shows complex interactions among heuristic and systematic processing and cognitive capacity. Finally, this issue includes a book review by Joslyn Zale, who reviews the recent book The Flaw of Averages (John Wiley and Sons). In the book, author Sam Savage presents concepts about the incorrect use of statistics in innovative ways, including providing many interesting examples. She recommends the book for those in the business and finance sectors who use statistics to make decisions and predictions, or for supplementary material for professors teaching courses in statistics.