It will rain: The effect of information on flood preparedness in urban Mozambique
中文摘要
洪灾是损失最惨重、发生最频繁的自然灾害之一。许多政府提供灾害防备信息，但关于其有效性的证据仍然有限。利用在莫桑比克300个城市社区开展的一项随机实验，本文表明，提供洪灾风险信息提高了建议减灾策略的实施程度——这一结果既通过客观测量得到证实（使用基于机器学习的算法，在超过25,000张照片中识别作为主要洪灾隐患的固体废弃物），也通过自报行为得到证实。发送洪灾防备短信被证明至少与更为资源密集的干预措施（包括入户走访和视频放映）同样有效。风险感知有所提高，尤其是在风险较低的地区，这表明信息与既往经历会通过塑造人们感知到的洪灾风险，促进社区备灾。这些发现凸显了沟通在动员社区开展灾害风险管理中的重要性，即使在洪灾风险据推测已广为人知的情境下亦是如此，也彰显了低成本、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.