Shih-Kai Huang

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...

Perceptions and expected immediate reactions to tornado warning polygons

To provide people with more specific information about tornado threats, the National Weather Service has replaced its county-wide warnings with smaller warning polygons that more specifically indicate the risk area. However, tornado warning polygons do not have a standardized definition regarding tornado strike probabilities (ps) so it is unclear how warning recipients interpret them. To better understand this issue, 155 participants responded to 15 hypothetical warning polygons. After viewing each polygon, they rated the likelihood of a tornado striking their location and the likelihood that they would take nine different response actions ranging from continuing normal activities to getting in a car and driving somewhere safer. The results showed participants inferred that the ps was highest at the polygon’s centroid, lower just inside the edges of the polygon, still lower (but not zero) just outside the edges of the polygon, and lowest in locations beyond that. Moreover, higher ps values were associated with lower expectations of continuing normal activities and higher expectations of seeking information from social sources (but not environmental cues) and higher expectations of seeking shelter (but not evacuating in their cars). These results indicate that most people make some errors in their ps judgments but are likely to respond appropriately to the ps they infer from the warning polygons. Overall, the findings from this study and other research can help meteorologists to better understand how people interpret the uncertainty associated with warning polygons and, thus, improve tornado warning systems.

Multistage Model of Hurricane Evacuation Decision: Empirical Study of Hurricanes Katrina and Rita

AbstractThis study extends previous research by testing the protective action decision model (PADM) on hurricane evacuation decisions during Hurricanes Katrina and Rita. An examination of this medi...

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.

Public reactions to the 2013 Chinese H7N9 Influenza outbreak: perceptions of risk, stakeholders, and protective actions

This study used the Protective Action Decision model to guide a survey of 762 respondents in Anhui province, China during the 2013 Avian Influenza A (H7N9) outbreak. The data suggest that three types of psychological variables – risk perceptions, protective action perceptions, and stakeholder perceptions – influenced people’s behavioral expectations of adopting protective actions. In addition, the effects of demographic variables on behavioral expectations were quite variable, with some being unrelated to behavioral expectations, some being related but unmediated by the psychological variables, and others being either partially or completely mediated by the psychological variables. These results can help public health officials to communicate more effectively when encouraging people to protect themselves during an influenza emergency.

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.

Perceptions and Expected Immediate Reactions to Severe Storm Displays

The National Weather Service has adopted warning polygons that more specifically indicate the risk area than its previous county-wide warnings. However, these polygons are not defined in terms of numerical strike probabilities (ps ). To better understand peoples interpretations of warning polygons, 167 participants were shown 23 hypothetical scenarios in one of three information conditions-polygon-only (Condition A), polygon + tornadic storm cell (Condition B), and polygon + tornadic storm cell + flanking nontornadic storm cells (Condition C). Participants judged each polygons ps and reported the likelihood of taking nine different response actions. The polygon-only condition replicated the results of previous studies; ps was highest at the polygons centroid and declined in all directions from there. The two conditions displaying storm cells differed from the polygon-only condition only in having ps just as high at the polygons edge nearest the storm cell as at its centroid. Overall, ps values were positively correlated with expectations of continuing normal activities, seeking information from social sources, seeking shelter, and evacuating by car. These results indicate that participants make more appropriate ps judgments when polygons are presented in their natural context of radar displays than when they are presented in isolation. However, the fact that ps judgments had moderately positive correlations with both sheltering (a generally appropriate response) and evacuation (a generally inappropriate response) suggests that experiment participants experience the same ambivalence about these two protective actions as people threatened by actual tornadoes.

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.