provide the public with alerts? What implications does the 90-character limit have for public response?

  • Can such a short message provide enough information to let individuals know that a significant event has taken place? Does it provide enough information for individuals to obtain additional information and take appropriate action to protect themselves?

  • What are the message characteristics that lead to effective instruction in crisis situations?

  • What does the public want the alert or warning message to say? What do they need to hear?

  • To what extent will CMAS alerts trigger information-seeking behaviors, and what forms will such behavior take? Might that information-seeking behavior end up leading to the network overloads that the Commercial Mobile Service Alert Advisory Committee (CMSAAC) voiced concern about?

Message Dissemination

Segments of the population are becoming increasingly accustomed to receiving mobile text messages, including alerts and warnings, from other individuals, from businesses, and from government agencies. Indeed, there has been some experience with the use of text alerts in municipal and countywide systems as well as some research looking at the effectiveness of these systems, but there has been no experience with national-scale systems. Moreover, the user bases for the systems in place today are small, and participation is entirely on an opt-in basis—so these systems only reach users who are most interested in receiving such alerting information. Where opt-out systems have been established, such as at the Virginia Polytechnic Institute and State University, the populations have been relatively small and centered around a particular institution. In contrast, CMAS will establish a large-scale opt-out system that covers much of the general population. Following is a list of unanswered questions about how the general public might respond to CMAS messages:


  • What are the consequences of too few messages (e.g., if the threshold for alerts is set too high or messages are repeated too infrequently)?

  • How does an alerts and warnings system generate the credibility needed to garner attention and guide the public’s response?

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