The CDC Clear Communication Index Is an Evidence-Based Approach to Clarity

Theoretical Background and research questions/hypothesis:  A fundamental tenet of communication is that a person or organization sends a message that is received by another person or organization, who interprets the message. Ideally, sender and receiver interact to make sure that the message was interpreted as the sender intended. In public health communication, knowing how audiences receive and interpret messages can be challenging. Oftentimes, senders of public health messages must rely on evidence-based criteria to increase the likelihood that audiences will receive messages as intended. The CDC Office of the Associate Director of Communication (OADC) posed two research questions about public health messages: which criteria does the research literature say have the greatest effect on message clarity, and do audiences react more positively to messages created using these criteria?

Methods:  An OADC-led research team followed a nine-step, literature review-based process that found over 200 factors that affect information clarity. These factors were reduced through repeated testing to 4 open-ended questions and 20 scored items aggregated into the CDC Clear Communication Index. The final step consisted of two online surveys to validate the Index: (1)  an online survey of a Web panel that provided a large sample reflective of U.S. adults; and (2) an online survey of a convenience sample of CDC.gov visitors who subscribe to CDC’s “What’s New on the Influenza site.” The studies were reviewed and approved by an IRB and the federal Office of Management and Budget. In both studies, the respondents were asked to evaluate one original CDC material or one Index re-designed material.

Results:  Survey respondents identified the main message and evaluated nine other factors about the material they viewed. For nine out of ten questions, the materials revised using the Index were rated higher than the original materials. Regardless of education, respondents rated the Index-revised materials more favorably than the original ones. On average, 22% more people stated the correct main message when they saw a revised material compared to those who saw an original material. Fewer respondents who saw the revised material said it included words unfamiliar to them compared to those who saw the original material (15% versus 30%) or numbers unfamiliar to them (6% versus 14%).

Conclusions:  The results indicate the CDC Index performed as intended and made it more likely that audiences could correctly identify the intended main message and understand words and numbers in the materials. The results also support the widely-held view that audiences are more positive about clearly designed materials. The CDC Index shows that an evidence-based scoring rubric can assess and improve the clarity of health materials.

Implications for research and/or practice:  Researchers who include the Index in their research may be able to offer additional evidence for Index items, as well as add evidence for new items that currently lack a strong evidence base, such as how to layer information for different audiences and purposes. Public health professionals can use the CDC Index to assess and develop materials for the many audiences they communicate with.