Acting on health literacy principles in a large agency requires not only knowledge of the research base, but also creative work to implement the concepts in practice. Sound scientific advice needs practical development, shaped for the specific working environment. For example, the U.S. Food and Drug Administration (FDA) needs to test communications with intended audiences, but must work within constraints including:

• Widely varied audiences

• Significant time pressure

• Complying with multiple reviews designed to protect potential message testers

Testing messages with the intended audiences is a basic communications responsibility, not just an option. Yet, how to do the testing can be challenging. The FDA’s experience suggests two practical approaches for user testing:

• Internal message testing with a network of employee volunteers

• External message testing with consumer panelists

The report briefly explains how the FDA assesses some public communication internally and externally to attain insights about a target audience or a health message as well as discover how a communication might be modified to improve its usability by an intended audience. The report suggests internal or external message testing is superior to controls (no testing) and such testing can be accomplished by a large governmental agency embedded within a complex regulatory environment.