Although the problem remains largely invisible, millions of Americans have a hard time reading. As many as half of U.S. adults have limited literacy skills.²
Even more Americans—as many as 9 out of 10—have limited health literacy skills. This means they have trouble understanding complex health information.² As more health information and services move online, Web developers and professionals must find new and better ways to communicate health information to the public.
The number of older adults using the Internet continues to grow. A significant number of older Web users are searching for health information. However, age-related changes in vision, hearing, and cognition affect older adults' use of the Internet.³

Taken individually, each of these factors presents a challenge for Web developers and health professionals. Taken together, they represent an urgent need for innovative design—and redesign—of health content on the Web.

Several factors affect how well users can find, understand, and use information on the Web, including:

Access to computers and experience online
Ability to read and understand printed text
Complexity of information on the Web
Usability of the Web in general and Web sites specifically^4,5

Clearly written content, uncluttered Web sites, and simple navigation dramatically improve the performance and experience of Web users, including those with limited literacy skills.

Studies show that simplifying your Web site improves the experience of all users, not just those with limited literacy skills.^4,6 Clean layouts and familiar language are more usable for everyone.⁷

Building On the Principles of Usability

The latest research in Web design supports creating easy-to-use Web sites. This guide builds on the principles of Web usability and adds to existing best practices by providing research-based strategies for writing and designing health Web sites that are accessible to users with limited literacy and limited health literacy skills.

Drawing on experience with healthfinder.gov, this guide synthesizes lessons learned from ODPHP's original research with more than 700 Web users and the small but growing body of literature on the Web experiences of users with limited literacy skills. The strategies outlined in this guide are supported by the Research-Based Web Design and Usability Guidelines, 2nd edition (Usability Guidelines),⁸ developed by the U.S. Department of Health and Human Services in partnership with the General Services Administration. The relevant chapters of the Usability Guidelines are listed at the end of each section.

Terminology: Literacy and Health Literacy

"Literacy" is a person's ability to read, write, speak, and solve problems at levels needed to function in society.⁹
"Health literacy" is a person's capacity to find, understand, and use basic health information and services needed to make appropriate health decisions.¹⁰

Although literacy and health literacy are distinct constructs, they are closely related. Literacy has been found to be a predictor of health literacy.¹¹ Roughly 1 in 3 adults has limited literacy skills; however, a far greater number of adults (as many as 9 in 10) struggle with complex health information.^2,11 In other words, a person may be extremely literate and still have difficulty interpreting and acting on health information—whether it's online or in print.

The aim of creating easy-to-use health Web sites is to reach as many Web users as possible, especially those adults who are overwhelmed by everyday literacy tasks. For this reason, this guide refers to Web users with limited literacy skills; it's assumed that these Web users, and millions more, likely have limited health literacy skills as well.

A Note on the Research

Most of the recommendations in this guide are based on original research studies conducted on behalf of ODPHP (detailed in Appendix D). ODPHP used proxy measures to identify a sample of adults with limited literacy and limited health literacy skills based on statistics from the health literacy component of the 2003 National Assessment of Adult Literacy. Individuals included in many of the studies referenced in this guide met the following criteria:

High school education or below
Below the poverty threshold
Have not searched for health information online in the past year

Participants were recruited from community settings likely to serve people with limited literacy and health literacy skills, including federally funded community health centers.

ODPHP's studies pertain specifically to the delivery of online health promotion and disease prevention content. Much of the research focused on communicating actionable information and motivating users to adopt healthy behaviors. The communication and usability strategies outlined in this guide also apply more generally to the delivery of health information on the Web.

Throughout the guide, we incorporate quotes from Web users with limited literacy skills who participated in our usability studies. These quotes speak to the valuable role Web users play in writing and designing effective Web sites.