Health literacy is the ability to read, understand and use healthcare information to make decisions and follow instructions for treatment. There are multiple definitions of health literacy, in part because health literacy involves both the context (or setting) in which health literacy demands are made (e.g., health care, media, Internet or fitness facility) and the skills that people bring to that situation (Rudd, Moeykens, & Colton, 1999). Studies reveal that up to half of patients cannot understand basic healthcare information. Low health literacy reduces the success of treatment and increases the risk of medical error. Various interventions, such as simplified information and illustrations, avoiding jargon, "teach back" methods and encouraging patients questions, have improved health behaviors in persons with low health literacy. Health literacy is of continued and increasing concern for health professionals, as it is a primary factor behind health disparities. The Healthy People 2020 initiative of the United States Department of Health and Human Services has included it as a pressing new topic, with objectives for addressing it in the decade to come.
There are many factors that determine the health literacy level of health education materials or other health interventions. Reading level, numeracy level, language barriers, cultural appropriateness, format and style, sentence structure, use of illustrations, interactiveness of intervention, and numerous other factors will affect how easily health information is understood and followed.
A study of 2,600 patients conducted in 1995 by two US hospitals found that between 26% and 60% of patients could not understand medication directions, a standard informed consent or basic health care materials.
The young and multidisciplinary field of health literacy emerged from two expert groups; physicians, other health providers, and health educators, and Adult Basic Education (ABE) and English as a Second Language (ESL) practitioners. Physicians are a source of groundbreaking patient comprehension and compliance studies. Adult Basic Education / English for Speakers of Languages Other Than English (ABE/ESOL) specialists study and design interventions to help people develop reading, writing, and conversation skills and increasingly infuse curricula with health information to promote better health literacy. A range of approaches to adult education brings health literacy skills to people in traditional classroom settings, as well as where they work and live.
Biomedical approach 
The biomedical approach to health literacy that became dominant (in the U.S.) during the 1980s and 1990s often depicted individuals as lacking, or “suffering” from, low health literacy, assumed that recipients are passive in their possession and reception of health literacy, and believed that models of literacy and health literacy are politically neutral and universally applicable. This approach is found lacking when placed in the context of broader ecological, critical, and cultural approaches to health. This approach has produced, and continues to reproduce, numerous correlational studies.
Where there are adequate levels of health literacy, that is where the population has sufficient knowledge and skills and where members of a community have the confidence to guide their own health, people are able to stay healthy, recover from illness and live with disease or disability.
McMurray states that health literacy is important in a community as it addresses health inequities, as those at the lower levels of health literacy are often the ones who live in lower socio-economic communities. Being aware of information relevant to improving their health, or how to access health resources creates higher levels of disadvantage. For some people, a lack of education and health literacy that would flow from education prevents them from becoming empowered at any time in their lives.
A more robust view of health literacy includes the ability to understand scientific concepts, content, and health research; skills in spoken, written, and online communication; critical interpretation of mass media messages; navigating complex systems of health care and governance; and knowledge and use of community capital and resources, as well as using cultural and indigenous knowledge in health decision making (Nutbeam, 2000; Ratzan, 2001; Zarcadoolas, Pleasant, & Greer, 2002). This view sees health literacy as a social determinant of health that offers a powerful opportunity to reduce inequities in health.
This perspective defines health literacy as the wide range of skills, and competencies that people develop over their lifetimes to seek out, comprehend, evaluate, and use health information and concepts to make informed choices, reduce health risks, and increase quality of life (Zarcadoolas, Pleasant, & Greer, 2006). While definitions vary in wording, they all fall within the conceptual framework offered in this definition.
Defining health literacy in that manner builds the foundation for a multi-dimensional model of health literacy built around four central domains:
- fundamental literacy,
- scientific literacy,
- civic literacy, and
- cultural literacy.
Patient safety and outcomes 
According to an Institute of Medicine (2004) report, low health literacy negatively affects the treatment outcome and safety of care delivery. These patients have a higher risk of hospitalization and longer hospital stays, are less likely to comply with treatment, are more likely to make errors with medication, and are more ill when they seek medical care.
The mismatch between a clinician's level of communication and a patient's ability to understand can lead to medication errors and adverse medical outcomes. The lack of health literacy affects all segments of the population, although it is disproportionate in certain demographic groups, such as the elderly, ethnic minorities, recent immigrants and persons with low general literacy. Health literacy skills are not only a problem in the public. Health care professionals (doctors, nurses, public health workers) can also have poor health literacy skills, such as a reduced ability to clearly explain health issues to patients and the public. A well arranged layout, pertinent illustrations, and intuitive format can improve the usability of health care literature. This in turn can help in effective communication between health care providers and patients and their families.
Risk identification 
Identifying patients at risk due to low health literacy is productive. Health behaviors such as correct medication use, taking advantage of health screening and effective preventive measures such as exercise and smoking cessation improved when low literacy patients were given visual aids, easy readability brochures or videotapes. Several tests of health literacy have been developed to validate research studies, but a practical, three-minute assessment can be completed in a doctor's office. A recent review on health literacy in the Journal of the American Medical Association's "Rational Clinical Examination Series" showed that single-item questions can be useful. The simple inquiry, "How confident are you in filling out medical forms by yourself?" gives a likelihood ratio (LR) for limited literacy of 5.0 (95% confidence interval [CI], 3.8-6.4) for an answer of "a little confident" or "not at all confident"; an LR of 2.2 (95% CI, 1.5-3.3) for "somewhat confident"; and an LR of 0.44 (95% CI, 0.24-0.82) for "quite a bit" or "extremely confident."
Once identified, low health literacy patients benefit from providing limited but clear information at each visit, avoidance of medical jargon, using illustrations of important concepts and confirming information by a "teach back" method. A program called "Ask Me 3" is designed to bring public and physician attention to this issue, by letting patients know that they should ask three questions each time they talk to a doctor, nurse, or pharmacist:
- What is my main problem?
- What do I need to do?
- Why is it important for me to do this?
A public information program by the US Department of Health and Human Services encourages patients to improve healthcare quality and avoid errors by asking questions about health conditions and treatment.
The book, Decoding Medical Gobbleddygook - Health Literacy Puts Patients First, has a lot of resources on improving health literacy and is available free online.
Diabetes is a rapidly growing health problem among immigrants—affecting approximately 10 percent of Asian-Americans. It is the fifth-leading cause of death in Asian-Americans between the ages of 45 and 64. In addition, type 2 diabetes is the most common form of the disease. Those who are diagnosed with type 2 diabetes have high levels of blood glucose because the body does not effectively respond to insulin. It is a lifelong disease with no known cure. Diabetes is a chronic, debilitating, and costly social burden—costing healthcare systems about $100 billion annually.
Diabetes disproportionately affects underserved and ethnically diverse populations, such as Vietnamese-American communities. The relationship between the disease and health literacy level is in part because of an individual’s ability to read English, evaluate blood glucose levels, and communicate with medical professionals. Other studies also suggest lack in knowledge of diabetes symptoms and complications. According to an observational cross-sectional study conducted, many Vietnamese-American diabetic patients show signs of poor blood glucose control and adherence due to inadequate self-management knowledge and experience. Diabetes health literacy research is needed to fully understand the burden of the chronic disease in Vietnamese-American communities, with respect to language and culture, health literacy, and immigrant status. Ethnic minority groups and immigrant communities have less knowledge of health promoting behavior, face considerable obstacles to health services, and experience poor communication with medical professionals. According to a recent review, studies has supported an independent relationship between literacy and knowledge of diabetes management and glucose control, but its impact on patients has not been sufficiently described. With the demand of chronic disease self-management (e.g., diabetic diet, glucose monitoring, etc.), a call for cultural-specific patient education is needed to achieve the control of diabetes and its adverse health outcomes in low- to middle-income Vietnamese-American immigrant communities.
eHealth literacy 
eHealth literacy is a term that describes the relatively modern concept of an individual’s ability to search for, successfully access, comprehend, and appraise desired health information from electronic sources and to then use such information to attempt to address a particular health problem. Due to the increasing influence of the internet for information-seeking and health information distribution purposes, eHealth literacy has become an important topic of research in recent years. Stellefson (2011) states, “8 out of 10 Internet users report that they have at least once looked online for health information, making it the third most popular Web activity next to checking email and using search engines in terms of activities that almost everybody has done.” Though in recent years, individuals may have gained access to a multitude of health information via the Internet, access alone does not ensure that proper search skills and techniques are being used to find the most relevant online and electronic resources. The lines between a reputable medical source and an amateur opinion from a so-called expert can often be blurred; however the ability to differentiate between the two is becoming increasing important.
Health literacy requires a combination of several different literacy skills in order to facilitate eHealth promotion and care. Six core skills are delineated by an eHealth literacy model referred to as the Lily model. The Lily Model’s six literacies are organized into two central types: analytic and context-specific. Analytic type literacies are those skills that can be applied to a broad range of sources, regardless of topic or content (ie., skills that can also be applied to shopping of researching a term paper in addition to health) whereas context-specific skills are those that are contextualized within a specific problem domain (can solely be applied to health). The six literacies are listed below, the first three of the analytic type and the latter three of the context-specific:
- Traditional literacy
- Media literacy
- Information literacy
- Computer literacy
- Scientific literacy
- Health literacy
According to Norman (2006), both analytical and context-specific literacy skills are “required to fully engage with electronic health resources.” As the World Wide Web and technological innovations are more and more becoming a part of the health care environment, it is important for information technology to be properly utilized to promote health and deliver health care effectively.
See also 
- Adult Basic Education
- Health care
- Health promotion
- Health education
- Patient safety
- Nutrition Literacy
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- Teaching Patients with Low Literacy Skills by Doak, Doak, and Root free download of entire book
- Health literacy course and materials based at Harvard University led by Rima Rudd
- Health and Literacy Special Collection
- “A Selection of Health Literacy Articles and Research” published by Partnership for Clear Health Communication
- Health Literacy Consulting. Includes the full-text of many health literacy articles as well as links to numerous resources.
- Health Literacy Resource List for Educators, USDA NAL Food and Nutrition Information Center (PDF|76KB)
- Link to Literacy Assistance Center health literacy resources for adult literacy educators and health care providers
- Link to Infodyne.org - InfoDyne Health Literacy Project (IHLP) is a non-profit organization that was founded in response to an overwhelming need for advocacy, research and the production of better health education tools to increase the level of health literacy across communities and improve patient safety and quality of care. Our mission is to save lives by increasing the level of health literacy across the spectrum of healthcare.
- A collection of health literacy curricula
- A variety of free Health Literacy and Patient Safety resources from the American Medical Association Foundation
- Health Literacy Searchable Online Library Includes health literacy studies, review articles, curricula, health materials in languages other than English and aimed at specific demographic groups (Health Literacy Missouri)
- Using social media for improving health literacy. In: THE SOLID FACTS - Health Literacy: Enabling healthier decisions in the 21st century. Copenhagen, Denmark: World Health Organization Regional Office for Europe, due Oct 2012 (in press)