The National Institute of Standards and Technology (NIST)'s Technical Investigation of the 2011 Joplin, MO tornado identified that no widely accepted standards exist for emergency communications in tornado events and more specifically, policies involving the use of communication systems to alert the public in advance of tornadoes.This study is designed to develop evidence-based guidance for communities on the creation and provision of public alerts, including both alerts provided by outdoor siren (warning) systems and "short messages" sent by social media or other short message service (SMS) platforms. It is the hope that this guidance can eventually be used as input for standardization, through codes and standards, of the procedures and practices for outdoor siren systems and short message alerts used by communities across the United States. Standardization of emergency communication policies and procedures could occur at multiple levels, including among multiple jurisdictions, state-wide, regionally, or even nationally.This document focuses on short message alerts, specifically presenting a review of platforms, usage and public response. First, an overview is provided on the current status of short message alerts in the United States, i.e., the current short message technology available and the ways in which this technology is used in communities across the United States. Second, a review of the literature is presented on the ways in which people respond to short message alerts and the current limitations of these systems in light of these findings. This document concludes with a discussion on the key findings and recommendations from the literature on the ways in which to improve current short message alerts, based on the methods by which people receive and process these types of alerts. Following this work, a document will be developed to provide the overall evidence-based guidance for communities on the creation and provision of public alerts.