Short-term panel data analysis of the effect of flood risk communication on individual evacuation decisions

People-centered risk communication is important to mitigate flood damage caused by the recent increase in heavy rainfall. Longitudinal studies are particularly important for evaluating the effectiveness of different risk communication methods. However, there is a lack of sufficient research. We conducted a longitudinal study, specifically through four panel surveys conducted over a short period of time, to investigate the effects of various risk communication methods, such as a simulated evacuation experience with learning about flood damage, flood-related information distribution including information about the evacuation behavior of others, and hazard maps. The results of a fixed effects analysis of the panel data suggest that the manner in which risk communication is affected varies depending on the initial evacuation attitude. In particular, we found that the distribution of hazard maps had a negative effect on the evacuation behavior of those who initially responded that they would evacuate. This suggests that residents in non-flood-prone areas may have acquired correct hazard perceptions from the hazard maps. However, for those who initially chose not to evacuate, confirmation of the delivered content had a positive effect on their evacuation behavior 12 hours before the typhoon hit. This suggests that those who initially chose not to evacuate may have reconsidered their decision. The risk communication presented in this study may help future risk communication by reducing congestion at evacuation sites due to excessive evacuation, while increasing the evacuation rate of those who should evacuate.