Mobile devices are everywhere, making them the ideal mechanisms for distributing immediate notices and alerts to the public. Preceding or during a natural disaster or emergency situation, some public safety agencies have used the Wireless Emergency Alerts (WEA) service to pass relevant information to the public. To find out how to make the most of these messages when alerting the public, DHS Science &Technology Directorate’s First Responders Group (FRG) funded the University of Maryland, National Consortium for the Study of Terrorism and Responses to Terrorism (START) to study “Comprehensive Testing of Imminent Threat Public Messages for Mobile Devices.” The study examined varying WEA message lengths and how the size of messages enhanced the recipients’ understanding of the message or influenced the recipient to take action.
The START research team conducted experiments, surveys, focus groups and interviews to determine how WEA messages could best motivate the public to take the recommended protective actions. The team discovered that message content, along with the order of message information, influenced the level of effectiveness. The researchers found messages were best understood when they were 1,380-characters, an optimal length, when a reliable source was named and when the most important pieces of information came first. Additional findings of the study include:
- The message should provide guidance, consequences of inaction and a deadline for taking action.
- Shorter messages (between 90- and 140-characters) were not as effective as longer messages in instructing people to take protective action.
- When visuals, such as maps, are included in the message, recipients remembered the information and felt encouraged to take protective action.
- WEA messages should include a message start time and use words such as “now” or “immediately.”
The WEA system went live in April 2012, allowing 90-character emergency alert messages to be broadcast by commercial mobile service providers to subscriber cell phones and pagers. WEA is a part of the U.S. Federal Emergency Management Agency’s Integrated Public Alert and Warning System, which allows emergency response agencies to simultaneously send alerts and warnings.
Further information on START’s WEA study can be found at: http://www.start.umd.edu/research-projects/comprehensive-testing-imminent-threat-public-messages-mobile-devices-mdp.