It will rain: The effect of information on flood preparedness in urban Mozambique
Journal of Development Economics · 2026 · [{"name": "Stefan Leeffers", "affiliation": ["University College London"]}]
中文摘要
洪水是代价最高且最频繁发生的自然灾害之一。许多政府提供灾害准备信息，但关于其有效性的证据有限。利用在莫桑比克300个城市社区开展的一项随机实验，我发现，提供洪水风险信息提高了建议减灾策略的实施；这一结果既通过客观方式衡量（使用基于机器学习的算法，在超过25,000张照片中检测作为主要洪水隐患的固体废物），也通过自我报告的行为衡量。发送洪水准备短信被证明至少与涉及入户访问和视频放映的、资源投入更密集的干预同样有效。风险感知有所提高，尤其是在风险较低的地区，这表明信息和过往经历通过塑造所感知的洪水风险而促进社区备灾。这些发现凸显了沟通在动员社区参与灾害风险管理中的重要性——即便在洪水风险被认为已广为人知的情境中也是如此——并强调了低成本、可扩展沟通工具的潜力。
Abstract
Floods are among the costliest and most recurring natural hazards. Many governments provide disaster preparedness information, but there is limited evidence of its effectiveness. Using a randomized experiment across 300 urban communities in Mozambique, I show that providing information on flood risk increased the implementation of suggested mitigation strategies, measured objectively (using a machine learning-based algorithm to detect solid waste, a major flood hazard, in over 25,000 photos) and through self-reported behaviors. Sending flood preparedness text messages proved to be at least as effective as more resource-intensive interventions that involved household visits and video screenings. Risk perception increased, particularly in lower-risk areas, suggesting that information and past experiences contribute to community preparedness by shaping perceived flood risk. These findings highlight the importance of communication in mobilizing communities for disaster risk management, even in contexts where flood risks are presumably already well-known, and underscore the potential of low-cost, scalable communication tools.