Analysis of citizen science program for disaster risk reduction in Japan: the case of Safecast

Abstract Citizen science is increasingly significant in scientific research and disaster management, especially as disaster risks intensify globally. While numerous studies confirm the value of citizen science programs in mitigating disaster risks, further research is needed to understand how these programs contribute to disaster risk reduction and to identify indicators of their success. This study investigates key success factors and challenges of citizen science programs through a case study of Safecast, a radiation monitoring initiative in Japan. Six critical factors were identified: active participation, knowledge production, data accuracy, expansion of spatial and temporal data, and citizen-related outcomes. Safecast’s broad engagement of participants, open-source data collection, and significant contributions to scientific research and policy decisions have been key to its effectiveness. In addition, the rigorous data accuracy measures and data expansion over time and space have further supported disaster risk reduction efforts. However, challenges remain in maintaining participant engagement, addressing the digital divide, and ensuring data consistency. Safecast exemplifies how citizen science can bridge grassroots data collection with formal disaster management, highlighting its potential to strengthen disaster resilience and empower communities.