prior to the inauguration, on January 14, 2009, there were about 70,000 subscribers. Within a month that number dropped to 40,000, only to start climbing again as the Cherry Blossom Festival approached in the spring.

Two educational issues related to subscription were noted as being important to communicate to the public. First, events can occur at any time, and alert services are important all the time, not just during large events. Second, it is important for individuals to subscribe to an appropriate set of alerts to ensure that they receive messages that are important for them to have but avoid receiving messages that they do not need. During registration for the alerts, people often sign up for all possible categories, but it is possible to tailor one’s registration for alerts to meet individual needs. For example, a person who commutes into the District of Columbia but lives in Virginia might want to register for severe-weather alerts only during work hours, which the system allows.

Subscription management is a challenge in both opt-in and opt-out systems. For example, in addition to delivering messages to people’s contact telephone numbers, Virginia Tech also delivers alerts to an employee’s or a student’s university-issued e-mail address. This provides for a redundant communications channel that helps ensure message receipt if the student or staff member is away from the telephone or has failed to keep their registered telephone number current.

A related issue is the ability to remove inactive names from the system, which both reduces the load on the system and prevents people from receiving alerts that no longer apply to them. At Virginia Tech, anyone not associated with the university for two consecutive semesters is automatically removed from the system. In the District of Columbia, the frequency of events encourages registrants to keep their information updated. However, the DC Alerts system also has numerous registrants who no longer live in the area—for example, interns or contractors who may reside in the city only for a short period of time often fail to remove their names from the system.


Virginia Tech alerts are focused on three key pieces of information: (1) the nature of the incident, (2) the location where the incident has occurred, and (3) the action to be taken. Often the action to be taken is simple, such as “Stay away” or “Stay indoors.” Virginia Tech uses subsequent messages to provide additional information and to point to other sources of information. Developing the content of these messages is complicated, and it can be difficult to satisfy those receiving messages.

The specific language used in an alert can matter greatly. For example, the use of the word “shooting” in the alert sent about the 2007 incident

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