Building a Better Message: The 10 Variables That Really Matter (The Reason) Galen Cole, PhD, MPH, LPC Centers for Disease Control and Prevention, Atlanta, GA Dr. Cole provides the background and purpose of the Message Development Tool (MDT) and describes the results of the expert panel meeting that assisted in the tool’s design. CDC’s Division of Cancer Prevention and Control created the Web-based MDT to enable health communicators to systematically and scientifically develop and validate effective health messages. Message mapping is a proven communication tool to deliver complex information in an easy-to-understand format for emergency and risk communication situations; however, such a tool does not currently exist for chronic disease messages.