Causal effects of time-sensitive risk communication on disaster preparedness

The growing threat of natural disasters underscores the urgent need for effective household preparedness. Governments promote disaster preparedness through public campaigns, yet their effectiveness remains unclear. This study evaluates the causal impact of earthquake advisories on preparedness by analyzing real-time behavioral data collected before and after the issuance of the Nankai Trough Earthquake Extra Information (Major Earthquake Advisory). This Advisory was triggered by a magnitude 7.1 earthquake in Hyuga-nada, Japan, on August 8, 2024, and alerted the public to an increased likelihood of a major earthquake. To estimate the causal effect of the Advisory on preparedness, we apply a difference-in-differences approach using data from a web-based survey conducted in August–September 2024, targeting individuals aged 20–69 residing in Osaka City, Japan. The treatment group comprises individuals aware of the Advisory, while those not aware serve as the control group. Our results indicate that the Advisory significantly increased preparedness actions, with a relative increase of 21.7%. Notably, it led to substantial increases in evacuation planning and stockpiling of emergency supplies, with relative increases of 61.1% and 26.9%, respectively. Unlike previous studies that found limited effects of government-issued warnings, our results demonstrate that time-sensitive advisories substantially enhance preparedness by raising public urgency. By leveraging real-time behavioral panel data, this study mitigates biases associated with retrospective surveys and strengthens causal inference. The findings provide empirical evidence supporting the effectiveness of timely and specific government-issued risk communication in enhancing disaster preparedness and contributing to the development of more effective emergency communication strategies.