A cross-hazard analysis of terse message retransmission on Twitter.

For decades, public warning messages have been relayed via broadcast information channels, including radio and television; more recently, risk communication channels have expanded to include social media sites, where messages can be easily amplified by user retransmission. This research examines the factors that predict the extent of retransmission for official hazard communications disseminated via Twitter. Using data from events involving five different hazards, we identity three types of attributes--local network properties, message content, and message style--that jointly amplify and/or attenuate the retransmission of official communications under imminent threat. We find that the use of an agreed-upon hashtag and the number of users following an official account positively influence message retransmission, as does message content describing hazard impacts or emphasizing cohesion among users. By contrast, messages directed at individuals, expressing gratitude, or including a URL were less widely disseminated than similar messages without these features. Our findings suggest that some measures commonly taken to convey additional information to the public (e.g., URL inclusion) may come at a cost in terms of message amplification; on the other hand, some types of content not traditionally emphasized in guidance on hazard communication may enhance retransmission rates.

What it Takes to Get Passed On: Message Content, Style, and Structure as Predictors of Retransmission in the Boston Marathon Bombing Response.

Message retransmission is a central aspect of information diffusion. In a disaster context, the passing on of official warning messages by members of the public also serves as a behavioral indicator of message salience, suggesting that particular messages are (or are not) perceived by the public to be both noteworthy and valuable enough to share with others. This study provides the first examination of terse message retransmission of official warning messages in response to a domestic terrorist attack, the Boston Marathon Bombing in 2013. Using messages posted from public officials' Twitter accounts that were active during the period of the Boston Marathon bombing and manhunt, we examine the features of messages that are associated with their retransmission. We focus on message content, style, and structure, as well as the networked relationships of message senders to answer the question: what characteristics of a terse message sent under conditions of imminent threat predict its retransmission among members of the public? We employ a negative binomial model to examine how message characteristics affect message retransmission. We find that, rather than any single effect dominating the process, retransmission of official Tweets during the Boston bombing response was jointly influenced by various message content, style, and sender characteristics. These findings suggest the need for more work that investigates impact of multiple factors on the allocation of attention and on message retransmission during hazard events.

Terse messaging and public health in the midst of natural disasters: the case of the Boulder floods.

Social media are quickly becoming the channel of choice for disseminating emergency warning messages. However, relatively little data-driven research exists to inform effective message design when using these media. The present study addresses that void by examining terse health-related warning messages sent by public safety agencies over Twitter during the 2013 Boulder, CO, floods. An examination of 5,100 tweets from 52 Twitter accounts over the course of the 5-day flood period yielded several key conclusions and implications. First, public health messages posted by local emergency management leaders are most frequently retweeted by organizations in our study. Second, emergency public health messages focus primarily on drinking water in this event. Third, terse messages can be designed in ways that include imperative/instructional and declarative/explanatory styles of content, both of which are essential for promoting public health during crises. These findings demonstrate that even terse messages delivered via Twitter ought to provide information about the hazard event, its impact, and actionable instructions for self-protection.