Abstract
Based on early evidence, risk communication scholars have come to believe that longer (360-character maximum) mobile public warning messages generate more compliance than shorter (90-character maximum) messages. This study used an experimental design to test that premise. The study measured participants' (N = 481) likelihood of compliance in response to a mock Wireless Emergency Alert (WEA) message, as well as alternatives to immediate compliance: seeking additional information, taking non-recommended action, or ignoring the message. The study found that both longer and shorter messages generated relatively high levels of compliance, but longer messages did not generate higher levels of compliance. Rather than message length, risk personalization and hazard experience were stronger differentiators of WEA message response outcomes. Results included a moderation effect: Shorter messages produced slightly greater compliance than longer messages among people who reported lower levels of risk personalization. The study concluded that 90-character messages may be more effective than previously believed. Consequently, the authors recommend renewed focus on public safety communication related to risk personalization and hazard experience. (169 words).