Emergency alerts are an efficient tool for keeping populations well informed during high-risk situations. In collaboration with Arlington County, our laboratory conducted a pilot study to identify messaging patterns that keep users engaged with their regional alert systems, focusing outreach efforts toward populations with the lowest levels of enrollment.

emergency weather alerts displayed on mobile phone


Emergency alerts help protect people by making local populations aware of emerging safety hazards or concerns. Increasing enrollment in the system is important for reaching a larger number of people. However, marketing the service and enrolling individuals can be a time-consuming and costly process. In addition, it is largely unknown at what point people reach notification fatigue and decide to un-enroll. Creating evidence-based strategies for targeting enrollment and retaining enrollees will help keep the community safer and better informed.

Arlington County and SDAL have partnered to utilize municipal and external data sources to help the region increase and retain individuals receiving emergency alerts. Officials were particularly interested in understanding the location of current enrollees, identifying populations with the highest levels of participation in the system, and uncovering links between enrollment rates and message frequency. 


SDAL researchers began by restructuring municipal data from Arlington County's alert system, merging it with federal and county information, and mapping the data geographically. Quantitative enrollment data was also merged with qualitative information such as the emotions expressed when users responded to a new alert.

Our team concluded by conducting an in-depth literature review to determine individual characteristics and occupations which made alert recipients more likely to share the information contained in their emergency notifications.


The data analysis revealed that the highest enrollment counts occur in Arlington County's metro corridor, which is a densely populated region. However, when enrollment location counts were weighted by population density of the location, it was revealed that the lowest enrollment areas were also some of the most vulnerable in terms of education and income. In addition, traffic and weather alerts tended to elicit the highest levels of un-enrollment behavior.

maps showing number of emergency alert subscribers by region

Based on these findings, Arlington County has implemented evidence-based policies to change their outreach and messaging strategy. They plan to direct outreach to areas with the lowest enrollment per capita as well as populations whose personal and professional roles are highly associated with information sharing, such as teachers and healthcare providers. In addition, they intend to reduce the number of traffic and weather alerts relayed through the system as repeated notifications frequently cause users to unsubscribe.

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