From alert to action: Social latency of citizen response to Cell Broadcast warnings during the ES-Alert drill in Gran Canaria (Spain)

Public alert systems based on Cell Broadcast technology are essential tools in emergency management, but their effectiveness depends not only on the technical speed in transmitting the message to the devices (technical latency) but also the time it takes for citizens to execute the recommended self-protection actions after receiving the messages (social latency). Cell broadcast is closely related to the so-called windows of opportunity, which are key factors in risk management. This study presents a pioneering evaluation of social latency in Spain during the ES-Alert drill conducted in September 2024 on the island of Gran Canaria (Spain), with a participation that exceeded 50,000 people. Through the analysis of timestamps associated with access to a digital survey sent with the alert, the citizen reaction times were determined. The results show that more than 70 % of the participants reacted in less than 10 min, with a median response time of 1 min and 12 s. Significantly faster responses were observed in urban and tourist municipalities compared to rural areas with lower technological penetration. Additionally, the system was positively rated by 91.4 % of the participants. Limitations include a ∼6 % response rate and the absence of device-level geocoordinates; location was self-reported at the municipality level only. The study highlights the importance of including social latency as a key metric in the evaluation of early warning systems, especially in insular and tourist contexts, and proposes the use of participatory strategies to improve risk communication and reinforce community resilience.