Hao-Che Wu

Household Evacuation Decision Making in Response to Hurricane Ike

AbstractThis study focused on household evacuation decisions and departure timing for Hurricane Ike. The data were consistent with an abbreviated form of the Protective-Action Decision Model in which female gender, official warning messages, hurricane experience, coastal location, and environmental and social cues were hypothesized to produce perceived storm characteristics, which in turn, would produce expected personal impacts. Finally, the latter, together with perceived evacuation impediments, would determine evacuation decisions and departure timing. However, there were fewer significant predictors of perceived storm characteristics and more significant predictors of expected personal impacts and evacuation decisions than hypothesized. Also contrary to hypothesis, female gender, perceived storm characteristics, official warnings, and hurricane experience predicted departure times. However, as expected, evacuation rates declined with distance from the coast; unlike Hurricane Rita 3 years earlier, ther...

Effects of track and threat information on judgments of hurricane strike probability

Although evacuation is one of the best strategies for protecting citizens from hurricane threat, the ways that local elected officials use hurricane data in deciding whether to issue hurricane evacuation orders is not well understood. To begin to address this problem, we examined the effects of hurricane track and intensity information in a laboratory setting where participants judged the probability that hypothetical hurricanes with a constant bearing (i.e., straight line forecast track) would make landfall in each of eight 45 degree sectors around the Gulf of Mexico. The results from 162 participants in a student sample showed that the judged strike probability distributions over the eight sectors within each scenario were, unsurprisingly, unimodal and centered on the sector toward which the forecast track pointed. More significantly, although strike probability judgments for the sector in the direction of the forecast track were generally higher than the corresponding judgments for the other sectors, the latter were not zero. Most significantly, there were no appreciable differences in the patterns of strike probability judgments for hurricane tracks represented by a forecast track only, an uncertainty cone only, or forecast track with an uncertainty cone-a result consistent with a recent survey of coastal residents threatened by Hurricane Charley. The study results suggest that people are able to correctly process basic information about hurricane tracks but they do make some errors. More research is needed to understand the sources of these errors and to identify better methods of displaying uncertainty about hurricane parameters.

Evacuees' information sources and reentry decision making in the aftermath of Hurricane Ike

In the aftermath of a hurricane, local emergency managers need to communicate reentry plans to households that might be scattered over multiple counties or states. To better understand evacuees’ households’ reliance on different information sources at the time they decided to return home, this study collected data on reentry after Hurricane Ike. The results from a survey of 340 evacuating households indicated that there was low compliance with official reentry plans and that none of the information sources produced greater compliance with official reentry plans. Nonetheless, there were significant changes in the utilization of different sources of emergency information over the course of an evacuation but local news media remained the most common sources throughout the event. There also were significant differences in the relative importance of different sources of reentry information, with people relying most on information from peers. In summary, local authorities need to identify more effective ways to communicate with evacuees that have relocated to distant communities and to motivate them to comply with official reentry plans.

Perceptions of protective actions for a water contamination emergency

Local authorities who believe their water systems are contaminated need to warn those at risk to take protective actions. In the past, such efforts have often achieved only partial success in preventing people from deciding to continue consumption of contaminated drinking water. To examine the possible antecedents of decisions to comply with water consumption advisories, this study examined 110 Boston residents’ actual protective actions and 203 Texas students’ expected protective actions; their perceptions of three protective actions on seven attributes; and their risk perceptions, water contamination experience, facilitating conditions, and demographic characteristics. The profiles of the protective actions for the hazard-related and resource-related attributes suggest reasons why people preferred to use bottled water rather than boil or personally chlorinate water. In particular, perceived effectiveness in protecting health was the most important correlate of protective action, which means that a protective action can have a high level of implementation even though it has poor ratings on other attributes such as cost. In addition, this study indicates public health officials may also need to address people’s misconceptions about the hazard-related and resource-related attributes of any relevant protective actions. Finally, consistent with an extensive body of previous research, students were similar to residents in many important respects even though were some statistically significant differences.

Perceptions, behavioral expectations, and implementation timing for response actions in a hurricane emergency

This study examined the perceived attributes, behavioral expectations, and expected implementation timing of 11 organizational emergency response actions for hurricane emergencies. The perceived attributes of the hurricane response actions were characterized by two hazard-related attributes (effectiveness for person protection and property protection) and five resource-related attributes (financial costs, required knowledge/skill, required equipment, required time/effort, and required cooperation). A total of 155 introductory psychology students responded to a hypothetical scenario involving an approaching Category 4 hurricane. The data collected in this study explain previous findings of untimely protective action decision making. Specifically, these data reveal distinctly different patterns for the expected implementation of preparatory actions and evacuation recommendations. Participants used the hazard-related and resource-related attributes to differentiate among the response actions and the expected timing of implementation. Moreover, participants’ behavioral expectations and expected implementation timing for the response actions were most strongly correlated with those actions’ effectiveness for person protection. Finally, participants reported evacuation implementation times that were consistent with a phased evacuation strategy in which risk areas are evacuated in order of their proximity to the coast. However, the late initiation of evacuation in risk areas closest to the coast could lead to very late evacuation of risk areas farther inland.

Behavioral Response in the Immediate Aftermath of Shaking: Earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan

This study examines people’s response actions in the first 30 min after shaking stopped following earthquakes in Christchurch and Wellington, New Zealand, and Hitachi, Japan. Data collected from 257 respondents in Christchurch, 332 respondents in Hitachi, and 204 respondents in Wellington revealed notable similarities in some response actions immediately after the shaking stopped. In all four events, people were most likely to contact family members and seek additional information about the situation. However, there were notable differences among events in the frequency of resuming previous activities. Actions taken in the first 30 min were weakly related to: demographic variables, earthquake experience, contextual variables, and actions taken during the shaking, but were significantly related to perceived shaking intensity, risk perception and affective responses to the shaking, and damage/infrastructure disruption. These results have important implications for future research and practice because they identify promising avenues for emergency managers to communicate seismic risks and appropriate responses to risk area populations.

A serendipitous, quasi-natural experiment: earthquake risk perceptions and hazard adjustments among college students

Hazard experience has been shown to influence risk perceptions, hazard salience, and the types of hazard adjustments people consider and undertake. Literature exploring the impact of experience on these constructs and decisions is, however, limited, with scholars often disagreeing on what counts as experience and lacking pre-event measures to compare to post-event outcomes. Given the difficulties in both predicting hazard occurrences with the temporal accuracy required to conduct pre-impact assessments close to the event and implementing surveys in a post-disaster environment, pre–post studies of disasters are rare. This study, by serendipity, achieved just this by distributing a survey exploring responses to techna earthquakes by college students in Oklahoma, receiving responses in the period just before and after the largest earthquake in modern Oklahoma history. In line with much of the existing literature, our results show that the Pawnee earthquake had significant impacts on respondents’ risk perceptions and hazard salience. Contrary to other findings, we did not find a relationship between hazard salience and hazard adjustments. Adjustments undertaken were predominately limited to information-seeking measures. Risk perceptions, of note, were more likely to be correlated with adjustment measures after the earthquake. This indicates that risk perceptions prior to the earthquake were not enough to motivate intention to adopt adjustments, but the Pawnee earthquake led those with heightened risk perceptions, along with others that had their risk perceptions positively influenced by the earthquake, to consider adopting hazard adjustments. We suggest that emergency managers use this window to encourage residents to undertake adjustment measures.

A tutorial on DynaSearch: A Web-based system for collecting process-tracing data in dynamic decision tasks

This tutorial describes DynaSearch, a Web-based system that supports process-tracing experiments on coupled-system dynamic decision-making tasks. A major need in these tasks is to examine the process by which decision makers search over a succession of situation reports for the information they need in order to make response decisions. DynaSearch provides researchers with the ability to construct and administer Web-based experiments containing both between- and within-subjects factors. Information search pages record participants’ acquisition of verbal, numeric, and graphic information. Questionnaire pages query participants’ recall of information, inferences from that information, and decisions about appropriate response actions. Experimenters can access this information in an online viewer to verify satisfactory task completion and can download the data in comma-separated text files that can be imported into statistical analysis packages.