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Evidence Reviews and Research Summaries

Here you will find the most recent evidence report on health literacy interventions and outcomes and brief research summaries on health literacy topics.

Health Literacy Evidence Reviews

Health Literacy Interventions and Outcomes: An Updated Systematic Review. The Agency for Healthcare Research and Quality (AHRQ) summarizes the evidence on health literacy and outcomes in a systematic review.

Research Summaries on Health Literacy Topics

CDC is committed to applying and sharing research to improve health literacy. In our Research Summaries section we present findings from recent published studies focused on specific health literacy topics. See our Science Bites for very brief summaries of select findings and recommendations for practice. Use these summaries to improve the effectiveness of your communication and program activities.

Health care professionals’ use of health literacy-based communication techniques

Patients need health care providers who can communicate clearly. Goal 2 of the National Action Plan to Improve Health Literacy outlines strategies all health professionals can use to identify and address health literacy barriers that negatively affect patient care and individual and community health outcomes.

Clinical professionals such as dentists, pharmacists, nurses, and physicians have an especially important role in improving health literacy and implementing strategies from the Action Plan.   This brief summary of research from 2011 to 2014 describes the use of health literacy-based communication strategies by health care professionals.

Dentists and Dental Hygienists

In a 2011 study, two-thirds or more of dentists reported using four communication techniques to ensure effective communication with patients and their understanding of oral health information.  These techniques include handing out printed materials, speaking slowly, using models or radiographs to explain, and using simple language.

These results were from a national survey to determine how frequently dentists use 18 communication techniques. The most commonly used technique was using simple language (90%). Teach-back techniques such as having the patient repeat information and repeat instructions were used by less than 24% of surveyed dentists.

A 2013 study of Maryland dentists found similar results. Over 93% of general dentists reported using simple language always or most of the time.  Teach-back techniques were much less used, with only 19% of general dentists asking patients to repeat information or instructions, and 35% asking patients to tell them what they will do at home to follow instructions. Pediatric dentists were more likely to ask patients to tell them what they will do at home to follow instructions (50%).

Results from health literacy environmental scans of community-based dental clinics are reported in a 2014 study.  One component of these scans involved assessing the frequency of dentists’ and dental hygienists’ use of recommended communication techniques. Use of teach-back was low.  Only 7% of providers indicated that they “always” use this technique; 22% indicated they use it “most of the time”; and 33% use it “occasionally”.   Techniques reportedly used “most of the time” or “always” include:

  • Limit number of concepts presented at a time to 2-3 (87%)
  • Use models or x-rays to explain (87%)
  • Use of simple language (99%)
  • Use a translator or interpreter when needed (75%)


Nurses’ use of communication techniques in encounters with type 2 diabetes patients was assessed in a nine-nurse qualitative 2014 study. Two to four encounters were recorded per nurse. Clarifying health information was the most commonly applied technique (58% often used), followed by repeating health information (33% often used). Checking for understanding was the least applied (81% never used), followed by asking for understanding (42% never used). Medical jargon and mismatched language were often used in 17% and 25% of the encounters, respectively.

Nurse practitioners’ knowledge, experience, and intention to use health literacy strategies were investigated in a 2013 study. The results show that overall knowledge of health literacy and health literacy strategies was low. Screening patients for low health literacy and evaluating patient education materials were found to be areas of knowledge deficit.  However, nurses’ intention to use health literacy strategies in practice was found to be strong.


In a 2013 pilot study, older adult patients reported on pharmacists’ use of health literacy-based techniques. The results are by proportion of patients reporting pharmacists’ behavior when the patient filled a new prescription.  

  • 89% of spoke to patients about how to take their medication
  • 84% spoke to patients about side effects
  • 47% discussed the problem for which the medication was prescribed
  • 26% communicated a plan for taking medications as prescribed
  • 39% explained what may happen if the medication is not taken as prescribed
  • 21% asked patients  to explain how they were going to take their medicine
  •  0% asked patients  to demonstrate how they were going to use their medicine


Results from a 2013 study reveal differences between medical residents’ self-reported communication behaviors and observed behaviors.   Residents reported frequent use of plain language (88%) and teach-back (48%).  However, their actual use of these techniques observed during low health literacy standardized patient encounters was much lower.  Residents used an average of two jargon terms per minute, and only 22% used teach-back.

Similar results were found in a 2013 study of medical resident’s communication with newly admitted patients to the emergency room.  Medical students observed internal and family medicine residents while they admitted patients to medical service in the emergency room.  Students used a checklist to assess interactions between residents and patients over an 8 week period.

In 52% of these interactions, residents used medical acronyms when communicating with patients.  Technical medical terms or expressions were used during the history taking in 66% of interactions, and less than 28% of those interactions included at least a partial explanation of terms.  Teach-back was not observed in any of the observed interactions.  Residents for whom English is a second language (ESL) used significantly more technical language than native English speaking residents, while native English speaking residents tended to use more acronyms.

A 2012 study of emergency physicians found the use of simple language and speaking slowly to patients as the only techniques a majority said  they used routinely  (92% and 61%, respectively). When asked about their perceptions of the effectiveness and feasibility of eight different communication techniques (shown below), a majority ranked all but “Reading aloud instructions” as effective, and the physicians said all eight were feasible in the emergency department.  

  • Using simple language
  • Speaking slowly
  • Underlining key points in patient information handouts
  • Presenting two concepts at a time and checking for understanding
  • Drawing pictures or using models to explain concepts
  • Reading aloud instructions
  • Asking patients how they will follow instructions at home
  • Asking patients to repeat information, teach-back technique

A 2014 study of radiation oncologists explores their understanding and awareness of health literacy among patients, their views regarding health literacy, and identifies techniques they use to communicate to different literacy populations. Participating oncologists report subjectively assessing a person’s literacy level by:

  • Monitoring the types of questions asked
  • Analyzing the language used
  • Examining non-verbal behavior
  • Considering a person’s socio-economic situation 

Participants reported the challenges of discussing the benefits and risks of cancer treatment options with lower literacy groups, and tended to provide the basic facts to facilitate understanding. 

Health literacy and medication labels, instructions, and regimens

Poor quality and variability of medication labeling have been cited as key contributors to medication misuse. Evidence suggests that health literacy plays a significant role in determining how well patients interpret medication labels and take nonprescription and prescription drugs safely and appropriately.  Recent research aimed at improving medication labeling is described below.

Medication Labels

A study published in 2013 finds a patient-centered label was better at preventing participants from exceeding the maximum dose in 24 hours, compared to a standard label. The patient-centered label did not significantly reduce other dosing errors such as taking more than two pills at a time and waiting fewer than four hours between doses.

A study investigating how parents use active ingredient information found many parents, especially those with low health literacy, do not use active ingredient information as part of decision-making related to administering multiple medications.  Overlapping active ingredients across multiple medications put children at risk for overdose.

A 2012 review of 200 top-selling pediatric oral liquid nonprescription medications found that labeling was often variable and in a format that may impair parent understanding of key medication information, including active ingredient information and dosing instructions.  Although most products listed active ingredients on the Drug Facts panel, 18.5% did not list active ingredients on the principal display panel.  Most products included directions in chart form, while few products expressed dosing instructions in pictographic form. 

In a 2011 study, less than 50% of focus group participants reported routinely examining product label information.  Only 31% were aware that acetaminophen is in Tylenol.  Participants achieved consensus on an icon to identify products that contain acetaminophen, a written statement warning of potential liver damage, and indicated a preference for an icon and wording for maximum daily dose.

Medication Instructions

Medication instructions are often the most tangible, frequently used source of information for patients on proper medication use.  However, they are often vague and unnecessarily complex.  Several studies explore how to improve patients’ comprehension of safe and appropriate medication use.

Medication guides were assessed by Wolf et al 2012 to determine their effectiveness in adequately informing patients on safe use.  Current medication guides were found to be of little value to patients, as they are too complex and difficult to understand especially for individuals with limited literacy.  In a follow-up study, the format and layout of three typical medication guides were modified to promote information accessibility.  Comprehension was significantly greater for all three prototypes compared with the current standard, and the guide modified according to health literacy best practices consistently demonstrated the highest scores, and reduced the effects of age and literacy disparities.

Patient preferences for how best to display patient medication information (PMI) were assessed in a study published in 2014. Similar to the Food and Drug Administration’s medication guides, PMI handouts are intended to help all consumers understand key information about their prescription medicine. Participants in one-on-one interviews noted their preference for new PMI handouts over existing medication guides or consumer medication information.  Although many preferences varied by age, education, and health status, most preferred to see drug information in a chunked format that is printed in a sans serif font, such as Arial. 

Patient opinions, preferences and comprehension of standard and improved medication instructions were assessed in a 2013 study.  Patients agreed on the need for simpler terminology and specificity in instructions.  Discussions addressed optimal ways of presenting numerical information, and indication and duration of use information to promote comprehension and safe use. 

In a study published in 2012, limited English proficient (LEP) patients receiving prescription medication instructions in their native language demonstrated significantly greater prescription understanding in comparison to those receiving standard instructions.  In most cases, instruction type was the sole, independent predictor of greater prescription understanding and demonstrated ability to correctly dose multiple prescriptions in multivariate models controlling for relevant covariates. 

Results from a study published in 2011 show the benefit of including pictographic dosing diagrams as part of written medication instructions for infant acetaminophen.  Parents receiving text-plus-pictogram instructions had higher dosing accuracy than parents receiving standard text-only instructions.  These differences were observed among parents with low health literacy, but not for parents with adequate health literacy.

Medication Regimens

Greater regimen complexity may lead to poorer adherence, which in turn will lead to worse health outcomes.  How patients manage their medication regimens, and the role health literacy plays, are explored in the studies described below.

Lenahan et al 2013 investigated drug regimen familiarity among a cohort of patients with hypertension. Specifically, the authors determined the prevalence of patients’ knowledge of their prescribed drug names and dosages compared to those who relied only on physical characteristics such as pill size, shape and color.  Patients dependent on the visual identification of their medicine reported worse adherence, lower rates of blood pressure control and greater risk of hospitalization.

A study published in 2013 explores the relationship between functional health literacy, medication-taking self-efficacy, and adherence to HIV/AIDS antiretroviral therapy.  Functional health literacy was not significantly related to either medication adherence or self-efficacy beliefs.  The authors suggest their measurement strategy as a possible explanation for this unexpected finding. 

Wolf et al 2011 investigate how well patients manage complex medication regimens that require them to consolidate dosing schedules throughout the day.  The finding that many patients, especially those with limited literacy, do not consolidate regimens efficiently supports the Institute of Medicine’s proposal of a universal medication schedule to standardize prescription practices to improve medication adherence.

Health literacy, patient activation, and health outcomes

Research summary: Health literacy, patient activation and health outcomes

A growing body of evidence shows individuals with the skills and confidence to become actively engaged in their health care have better health outcomes.  Ongoing research seeks to determine the relative contribution of measures of health literacy and patient activation to improved outcomes.  Some conceptualizations of health literacy include aspects of motivation and self-efficacy. However, other conceptualizations limit health literacy to a more skills-based construct that involves reading, math, speaking and listening abilities needed to make informed health decisions. While an individual’s motivation and confidence to engage in health self-management are often not measured as part of health literacy, they are included in measures of patient activation.

Below is a summary of recent research into these constructs, how they relate to each other, and their potential for improving outcomes such as health information seeking, comprehension and use, patient self-advocacy, mental and physical health, and costs.

Health literacy, patient activation and health information seeking, comprehension and use

A study published in 2014 investigates the relative contribution of patient activation and functional health literacy to the seeking and use of health information among adults in The Netherlands.  While the researchers acknowledge alternative definitions of health literacy, such as broader definitions that include aspects of motivation, skills and self-efficacy, they employ a functional definition limited to the basic reading and numerical tasks required to function in a health environment.  Among a sample from a consumer panel, they find patient activation to be a stronger predictor for seeking and using health information than functional health literacy. 

Two of the three items used to measure functional health literacy were significantly related to patient activation.  Those who were more confident with filling out medical forms had higher patient activation scores. Those who agreed with having problems learning about their medical condition because of difficulty understanding written information had lower patient activation scores.  Patient activation was not significantly related to receiving help from others with reading.

Hibbard, Peters, Dixon and Tusler (2007) assess the contribution of health literacy, numeracy and patient activation to the comprehension of comparative hospital performance reports, as well as quality choices based on that information.  They found numeracy skill to be the strongest predictor of both comprehension and quality choices. Health literacy was also a strong predictor of both.  Patient activation was only moderately predictive of comprehension and quality choices. However, activation was found to contribute more to the outcomes for those with lower numeracy and health literacy skills, compared to those with higher skills.  Thus, higher activation may compensate for lower skills. 

Health literacy, patient activation and mental and physical health

A study published in 2013 examines the association between health literacy and patient activation as they are most commonly measured among a cohort of older adults. They measured health literacy with the Test of Functional Health Literacy in Adults (TOFHLA) and measured patient activation with the Patient Activation Measure (PAM). The relationship between health literacy and patient activation was weak, but significant. The researchers also examine the independent and combined associations of health literacy and patient activation with physical and mental health.  Lower health literacy was associated with worse physical health and depression.  Lower patient activation was associated with worse physical health and depression, as well as anxiety. Patient activation was the stronger predictor of the two measures for all health outcomes.

Health literacy and patient self-advocacy

Martin et al (2011) examine whether reading, numeracy, speaking, and listening skills are associated with patient self-advocacy when faced with a hypothetical barrier to scheduling a medical appointment.  They define patient self-advocacy as the extent to which individuals demonstrate an increased assertiveness or willingness to challenge providers or other medical authority, and to actively participate in decision-making to ensure they receive the treatment they feel best meets their needs.  They found all literacy skills to be significantly associated with advocacy when examined in isolation. However, greater speaking and listening skills remained significantly associated with better patient advocacy when all four skills were examined simultaneously.

Patient activation and health outcomes and costs

A study published in 2015 examines the extent to which a single assessment of patient engagement, the Patient Activation Measure, was associated with health outcomes and costs over time.  The Patient Activation Measure is scored on a scale of 0 to 100 and indicates four levels of activation which reflect a progression from being passive with regard to one’s health to being proactive.  They found an association between higher activation and improved health outcomes, as well as lower costs, two years later.

Hibbard & Greene (2013) review the available evidence of the contribution of patient activation makes to health outcomes, costs, and patient experience.  In addition to finding evidence of higher activation being associated with better health outcomes and care experiences, they also find evidence that patient activation can be increased through intervention.

Health literate organizations and self-management support

Koh, Brach, Harris & Parchman (2013) propose a Health Literate Care Model that would infuse health literacy into all aspects of a health care organization, including planning and operations, self-management support, delivery systems design, shared-decision making support, clinical information systems to track and plan patient care, and helping patients access community resources.  Central to this model is the support of productive interactions at both the individual and organizational levels.  Perhaps most aligned with the concept of patient activation, the self-management support element of the Health Literate Care Model encourages patients to be empowered and prepared to manage their own health and health care. 

Nutritional and food literacy, food labels, and portion size estimation

Research summary: Nutritional and food literacy, food labels, and portion size estimation

Health literacy is used broadly to refer to how individuals understand, interpret, and apply health information. However, researchers continue to debate and define what it means to be nutritionally literate and food literate. While some researchers use nutritional literacy and food literacy synonymously, others distinguish the two and refer to nutrition literacy as going beyond understanding the origin of food, how it is cultivated and processed and its impact on health, to being able to act on nutritional information.

A growing body of research shows that individuals who accurately estimate portion sizes and interpret and use food labels have higher nutritional literacy and numeracy skills and realize better health outcomes. Using emolabels and strategies to ease comprehension may help children select more nutritious food and have healthy dietary behaviors. 

Below is a summary of recent nutritional and food literacy research, with emphasis on food labels, portion sizes, and dietary behaviors.

Children and food literacy

Privera et al. conducted a study in which children were asked to choose 4 out of 12 food items in a grocery aisle setting with emo-labels added (happy = healthy; sad = not healthy) and again without emo-labels. Children made overall healthier food choices when emo-labels were present, even when they knew about the unhealthy options available. Emo-labels may not only promote healthier food choices for children, but researchers contend that they may also be a good tool to help increase health literacy at an early age and potentially help reduce rates of childhood obesity.

A preschool program in Australia designed to increase children’s food literacy and encourage children to enjoy vegetables shows that food literacy begins at an early age. The curriculum consists of a one or two hour weekly session taught by dieticians, preschool staff and volunteers.  Whiteley & Matwiejczyk found that after the program, over 70% of children asked for and ate more vegetables and parents and preschool staff also reported that children were more knowledgeable about vegetables and had improved food literacy.

Health literacy skills and use of food labels

A 2014 study finds that young adults with poor health literacy are not likely to use food labels to select food products and are more likely to report an unhealthy diet.  People with higher self-efficacy use food labels more often.  When people use the information on food labels regularly, they tend to have better dietary choices and have better health outcomes. Another study also notes a correlation between poor food label comprehension and low literacy and numeracy skills.

A 2012 study examined the health literacy and nutrition behaviors of low income adults. Race and parental status were found to be significant predictors of health literacy among a sample of Supplemental Nutritional Assistance Program (SNAP) eligible adults. Only 37% of participants had adequate health literacy, as assessed by the Newest Vital Sign (NVS), a health literacy measurement tool, and less than half of them reported using nutrition labels when purchasing food.  Questions that required numeracy skills proved to be most challenging for participants.  

A 2015 study used eye-tracking glasses to measure adults’ visual attention to the nutritional information of food products during a food selection task. Front labels used a familiar red, yellow and green sign and there was a sign with explanatory information near the product. Back labels were the usual nutrition label. Nutrition labels located on the front of products were more likely to be viewed by participants than those located on the back, suggesting that consumers may be more willing to read the shortened and simplified labels.

Sinclair & Hammond investigated how well adults could comprehend food labels. They found that although people self-report high levels of understanding, their actual comprehension of food label information is much lower. Comprehension was lowest among most disadvantaged socioeconomic groups. Higher education and income, and White ethnicity positively correlated with correctly answering questions pertaining to percentage of daily nutritional value of food products. 

Portion Size

A 2011 study examined visual representations of food portion sizes on a web interface, noting that digital applications that help people keep track of their food intake are not always apt for people with low literacy or numeracy skills.   Researchers noted that it is difficult for people with low literacy to estimate portion sizes and their food intake.  Participants often preferred hand gestures such as the shape of a fist, or an extended palm to estimate portion size of shapeless foods, and were more accurate about estimating liquids and shapeless food items, rather than solids.

A study by Huizinga et al. found that although 91% of study participants reported completing high school, only 65% of them were accurate when asked to serve a single serving of food. Participants who overestimated how much food constitutes a single serving were much more likely to have low literacy and numeracy skills than adults who provided accurate estimates.

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Science Bites

Use pictures to improve health communication

Pictures that are closely linked to written or spoken text and have minimal distracting details can be helpful to individuals with low literacy skills. For evidence of how adding pictures to written and spoken language can increase the effectiveness of health education materials see: The role of pictures in improving health communication: A review of research on attention, comprehension, recall, and adherence. (2006)

Make orally delivered health information accessible and actionable

Just as written material can be made more reader-friendly, orally delivered health information can be made more accessible and actionable. For evidence of how the features of language and interactivity contribute to literacy see: Assessing oral literacy demand in genetic counseling dialogue: Preliminary test of a conceptual framework. (2007).

Use headings to help readers scan and find information

Headings can be helpful organizational elements that ease the reading and use of your materials. Remember, people read our materials because they want to understand something about their health, make a decision, and take action. Descriptive headings should clearly communicate the purpose of the material, who it is for, and how to use it. Readers can skim and make quick judgments about what's worth reading.
For evidence of how descriptive headings and simplified print presentations increase comprehension and recall of informed consent information among those with limited literacy skills see: The effect of format modifications and reading comprehension on recall of informed consent information by low-income parents: A comparison of print, video, and computer-based presentations. (2004)

Headings are also very important in webpage layout. See for instruction on how to use descriptive headings throughout a website to help users scan and find information quickly.

Use narrative communication

Public health information is often presented in numbers and statistics. However, the public may be disinterested or confused by scientific data. You can use narratives such as anecdotes, quotations, examples, vignettes, and personal stories to describe subjects your audience is familiar with. Narratives increase the chance your audience will pay attention to and remember information. Studies find narratives can lead to cancer-relevant belief and behavior change (Green, M.C., 2006) and to be more effective than statistical evidence on some patient outcomes (Mazor et al., 2007).

For more information about narratives and health communication see Hinyard, L.J. & Kreuter, M.W. (2007). Using Narrative Communication as a Tool for Health Behavior Change: A Conceptual, Theoretical, and Empirical Overview

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Chunk information to improve audience comprehension and recall

Readers can handle only a limited amount of information at one time. By grouping information into meaningful "chunks" of reasonable size, we can save our audience from experiencing information overload and improve their ability to organize and recall the material. Doak and colleagues suggest that readers with less education and training may not comfortably process more than 5 pieces of information at a time. See Chapter 5 [6.0 MB, 68 pages] from Doak, Doak, & Root, 1996, Teaching Patients with Low Literacy Skills for an example of how to chunk information.

To learn more about this topic see George A. Miller's classic article on recall that established about seven chunks as the brain's limit for holding information in short-term memory.

Explain risk and numbers

Practical, science-based advice on explaining risks and numbers includes using numbers rather than words alone to explain risk, providing absolute risk (10 out of 100), and keeping the denominators and time frames the same when making comparisons. See Communicating Risks and Benefits: An Evidence-based User's Guide from the U.S. Food and Drug Administration for more evidence on when and how to use numbers and explain risks to the public and patients.

Anticipate and assess audiences' emotional reactions to risk information

Every risk communication is processed both cognitively and emotionally….Success in a risk communication must be measured not only by what recipients know but by how they feel.
Zikmund-Fisher, Fagerlin & Ubel, 2010, Risky feelings: Why a 6% risk of cancer does not always feel like 6%, p. S92

Understand how numbers affect comprehension and decisions

Numeracy is related to perceptions of health-related risks and benefits. Participants lower in numeracy tent to overestimate the risk of cancer and other risk, are less able to use risk reduction information (e.g. about screening) to adjust their risk estimates, and may overestimate benefits of certain treatments.
Reyna, Nelson, Han & Dieckmann, 2009, How numeracy influences risk comprehension and medical decision making, p. 957

Design for improved comprehension among limited health literacy populations

The following specific design features seemed to improve comprehension for low-health-literacy populations in one or a few studies: (1) presenting essential information by itself (i.e. (sic) information on hospital death rates without other distracting information, such as information on consumer satisfaction); (2) presenting essential information first (i.e. (sic) information on hospital death rates before information about consumer satisfaction); (3) presenting health plan quality information such that the higher number (rather than the lower number) indicates better quality; (4) using the same denominators to present baseline risk and treatment benefit; (5) adding icon arrays to numerical presentations of treatment benefit; and (6) adding video to verbal narratives.
Berkman, Sheridan, Donahue, Halpern, et al. 2011, Health literacy interventions and outcomes: An updated systematic review, p. ES-7

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