Low literacy and written drug information: information-seeking, leaflet evaluation and preferences, and roles for images
Int J Clin Pharm
Low literacy and written drug information: information-seeking, leaflet evaluation and preferences, and roles for images
Mara M. van Beusekom 0 1 2
Petronella Grootens-Wiegers 0 1 2
Mark J. W. Bos 0 1 2
Henk-Jan Guchelaar 0 1 2
Jos M. van den Broek 0 1 2
0 Communication, Faculty Management and Organisation, The Hague University of Applied Sciences , The Hague , The Netherlands
1 Science Communication and Society, Leiden University , Leiden , The Netherlands
2 Clinical Pharmacy and Toxicology, Leiden University Medical Center , Leiden , The Netherlands
Background Low-literate patients are at risk to misinterpret written drug information. For the (co-) design of targeted patient information, it is key to involve this group in determining their communication barriers and information needs. Objective To gain insight into how people with low literacy use and evaluate written drug information, and to identify ways in which they feel the patient leaflet can be improved, and in particular how images could be used. Setting Food banks and an education institution for Dutch language training in the Netherlands. Method Semi-structured focus groups and individual interviews were held with low-literate participants (n = 45). The thematic framework approach was used for analysis to identify themes in the data. Main outcome measure Lowliterate people's experience with patient information leaflets, ideas for improvements, and perceptions on possible uses for visuals. Results Patient information leaflets were considered discouraging to use, and information difficult to find and understand. Many rely on alternative information sources. The leaflet should be shorter, and improved in terms of organisation, legibility and readability. Participants thought images could increase the leaflet's appeal, help ask questions, provide an overview, help understand textual information, aid recall, reassure, and even lead to increased Mara M. van Beusekom
Netherlands; Readability; Drug information; Literacy; Patient information leaflet; Visuals; Legibility; Pictograms
confidence, empowerment and feeling of safety. Conclusion
Already at the stages of paying attention to the leaflet and
maintaining interest in the message, low-literate patients
experience barriers in the communication process through
written drug information. Short, structured, visual/textual
explanations can lower the motivational threshold to use the
leaflet, improve understanding, and empower the
low-literate target group.
Impact of practice
Building on the identified problems and proposed
solutions presented by people with low-literacy allows
for the development of a targeted, co-designed
intervention to improve written drug information.
Pharmacists should consider using images in written
drug information that help to find and understand
relevant topics and lower the motivational threshold to
use the printed information.
Images in patient leaflets can help to empower patients
with low literacy.
Written drug information is generally difficult to read,
causing patients to struggle with the interpretation of their
medication instructions [1, 2]. This is a particular concern
for patients with low literacy skills , who also out of the
context of healthcare have difficulties with using printed
and written information as encountered in society . In
this light, it is of little surprise that there is a relation
between low (health) literacy levels and problems with safe
use of medication and adherence to therapy [5, 6]. This is
undesirable, as safe use of medication, including being
observant of side-effects and multi-drug interactions, as
well as proper adherence, is crucial for effective treatment
and to advance patient health outcomes [7, 8].
Despite the described shortcoming, written drug
information has important benefits compared to other
information sources, also for people with low literacy. For
example, patients generally have low retention of spoken
information . However, printed instructions, such as
Patient Information Leaflets (PILs) that are packed with
medicines, remain available for later reference and for
relations of the patients, such as family and caretakers .
To improve the usability and quality of written drug
information, visual aids can be used in conjunction with
text to facilitate understanding—an approach that has
proven to be particularly successful for people with low
literacy [11–14]. To further illustrate, already in 1996, Delp
and Jones  demonstrated that printed health
instructions with visuals were much more likely to be read by
patients than text-only materials. In addition to drawing
attention, there is ample proof that images can aid free and
cued recall [16–19].
This study explored the interaction between individuals
with low literacy and patient information, with the intention
to develop a visual/textual drug leaflet that is compatible
with the needs a low-literate audience. Active involvement
of the target group in the development process, or co-design,
has been shown to lead to successful health interventions
[20, 21]. To date, there is insufficient insight into the
communication barriers and information needs of the low-literate
target group, and there is a lack of studies that involve this
audience in the design of targeted patient leaflets.
Aim of the study
The aim of this study is to gain insight into how people
with low literacy use and evaluate written drug
information, and to identify ways in which they feel the patient
leaflet can be improved, and in particular how images
could be used.
Informed consent was obtained from all individual
participants included in the study. Following national regulations,
no ethical approval was required for this type of study.
Data were collected through individual interviews and focus
group discussions with participants with low literacy,
making use of a one-on-one approach to acquire detailed
information and group interactions to allow participants to discuss
and reach consensus. An iterative process allows the
researcher to build upon obtained results, and triangulate
data by identifying missing pieces of information and
confirming recurring stories . For example, if participants of
the focus group discussions do not feel they can speak freely
about personal issues in a group, this type of information
could potentially be shared in the individual interviews.
Following principles of human factors and ergonomics
, the target group was involved in the ‘fuzzy front end’
of the design process. In this step of the design process it is
determined what problems should be targeted and what the
product should look like .
McGuire’s communication/persuasion matrix will be used
to provide context to the interpretation of the results, as
previously suggested for health-related images by Houts . In his
model, McGuire describes how people, before being persuaded
by a (health-related) message, transit through 13 stages: tuning
in, attending, liking, comprehending, generating, acquiring,
agreeing, storing, retrieval, decision, acting, post-action, and
converting . Images fall under the input variable ‘message’,
which can be manipulated to affect the process of persuasion.
This strategy allows insight in exactly where images can play a
role in improving transition to the next phase of the
communication/persuasion process, according to the end-users.
Participants were recruited at three distribution points of a
food bank in The Hague (the Netherlands). Experienced
volunteers of the food bank asked clients if they were
interested to participate in the study. Clients were
approached of whom volunteers suspected through previous
encounters, for example, when filling out a form to register
with the food bank, had difficulty reading and writing. People
who expressed interest were explained the procedure by the
researcher, after which informed consent was obtained.
Duration of the interviews was on average 10–30 min.
To ensure that participants were indeed part of the target
group, literacy levels were determined using the
REALMD, a validated instrument to measure functional literacy in
health-related information in Dutch . The scores of the
included participants indicated they would have moderate
to severe problems to understand average patient
information (B60 words correct according to the
scorerequirements reprinted by ). For mean REALM-D
scores see Table 1.
Sixteen people were interviewed, of which two in a joint
interview. One participant was later excluded from analysis
because their REALM-D score was too high to be
representative for low literacy, so that the final n = 15. Most
participants were female (n = 13) and the average age was
43. None of the participants were educated beyond
secondary level. For eight participants, Dutch was (one of)
their native language(s), while seven people indicated to
have another first language.
Focus group discussions
For the focus group sessions, participants were recruited
from Dutch language classes at an educational institution
for adults who are fluent in Dutch, but have a low reading
and writing level (The Hague, the Netherlands). Interested
candidates were explained the procedure, after which
informed consent could be obtained. Group sizes ranged
from three to nine participants, and depending on the size,
discussions took between 30 and 60 min. The sessions
were moderated by author MvB and PG and carried out
with the instructor of the class present.
Literacy levels were not determined individually.
According to the educational institution, all included
participants had a reading level below 1 F in Meijerink’s
classification, the Dutch national standard—equivalent to a
reading level below that of children that finish primary
school . A total of 30 low-literate people took part in
this part of the study, distributed across five focus group
sessions. Most participants were female (n = 25), and the
average age was 47. Most of the participants were not
Table 1 Demographic data of
participants of individual
interviews and focus group
a One participant was present for both focus group 1 and 3, so that there are 44 unique ns
b Education levels according to Statistics Netherlands 
c This category also includes people from Surinam who only spoke Dutch at school from the age of 4
d This category also includes native speakers of Dutch
schooled to secondary education level. Sixteen
participants had Dutch as (one of) their native language(s), 14
Data collection and analyses
Data were collected between November 2013 and February
2014. All sessions were semi-structured and covered
questions on participants’ use of written drug information,
their evaluation of it, and suggestions for improvement. A
randomly selected standard patient information leaflet
ENA50005627D) was shown to initiate the discussion and to make sure
that the topic of ‘patient information leaflets’ more
Subsequently, the idea of adding images was discussed,
followed by a discussion on possible uses of images –to
facilitate the conversation, examples of images were
shown, including abstract signs (blue information sign,
yellow warning sign, and a red stop sign), and more
informative images (USP-pictograms: ‘‘take by mouth’’,
‘‘for heart problems’’, ‘‘take with glass of water’’, and ‘‘do
not take if pregnant’’) . Also, a sample of a
visual/textual leaflet  was shown, as an example of how
the addition of images could look for patient information,
to facilitate the discussion on possible benefits of adding
images. Additional rounds were held to discuss
participants’ preference concerning design style and topics for
visualisation—these results require their own framework
and will not be discussed here.
Audio recordings were transcribed between sessions so
that data-collection could be stopped when saturation in the
answers was reached. As is typical for focus group
discussions, the moderators frequently summarised findings
during the discussions and brought up answers that were
given in previous sessions, to verify findings as they were
gathered. Data were analysed using the thematic
framework approach as described by Ritchie and colleagues .
Author MvB identified initial themes, and after
independently applying this indexing framework to a subset of the
interviews, authors PG and MB discussed the framework
and themes in several rounds until consensus was reached.
Consequently, all data were labelled and summarised using
QDA Miner Lite.
Four main themes were identified in the interviews and
discussions: information-seeking strategies, evaluation of
written drug information, suggestions for improvement,
and roles for visuals.
Most participants indicated that they normally rely on
additional or alternative sources for medication instructions
to the PIL (Table 2). Some refer to the medicine
packaging, and a few participants said to look up words or
instructions online. The majority of participants who do not
read the leaflet rely on other people for their information:
usually their pharmacist, general practitioner, or family
members. A participant explained why she prefers this to
reading written instructions: ‘‘If I do read it, then I do not
understand everything. And if I get it a little wrong, I will
panic completely.’’ Although most participants had some
way to obtain their information, when asked in the focus
group discussion, several participants admitted to regret not
being able to gather information from the leaflet for
PIL evaluation and preferences
Tuning in, attending and liking stages
The majority of participants did not consider PILs to be
patient-friendly (Table 3). Both in the focus groups and
individual interviews it was mentioned that the text was too
long and the font size too small. Generally it was agreed
that an ideal leaflet consists of only one A4-sized sheet that
provides a clear overview of relevant information in a
legible font size.
Many participants indicated that the general appearance
of current leaflets was not inviting. As a participant stated:
‘‘I simply do not feel like reading it when I see it like that.’’
Those who read the leaflet often indicated that it is difficult
to work up enough motivation to read and process the
information in the leaflet, particularly if they feel unwell
and need to take the medication quickly. Similarly, most
participants said to prefer printed over digital medication
Table 3 Participants evaluation
and preferences for PILs
Participants’ evaluation of PILs
instructions, so that it is within easy reach. Also, a few
participants did not have regular access to a computer, so
that providing digital information alone would not suffice.
Finding relevant information in the leaflet was
considered too difficult by the majority. A participant explained
that ‘‘it is only in the middle and at the end that you can
find what is really important.’’ Regularly, the usefulness of
headings was mentioned to navigate the text: ‘‘I always
first look at the heading, the title of a section, and if this
seems to be information I need than I will read that section
of the text.’’
Comprehending, generating, acquiring stages
Most participants agreed that the patient leaflet is difficult to
read. A few participants mentioned their own reading level
in this context, but the unnecessary use of complex language
was considered the biggest problem. This was illustrated by
a participant’s comment: ‘‘The information is written in
Latin doctor language. It is the language of the pharmacy,
words of the general practitioner - not of ordinary people.’’
In addition to the use of simple language, it was suggested to
provide information in the user’s native language.
During the focus group discussions, participants came
up with the idea to add an area where people can take
notes, for example on when to take the next dose. When the
subject of visuals as a supplement to text was discussed,
some participants expressed that for them it was not
necessary, but the majority was enthusiastic – especially to use
images in combination with text.
Roles for visuals
Tuning in, attending, liking stages
Participants saw a variety of uses for images (Table 4).
Visuals were thought to make the leaflet more appealing,
less dull and daunting, and thereby more inviting to use.
Leaflets with visuals were expected to draw more attention
than leaflets without visuals. One participant stated:
Topics on PIL preferences
‘‘People generally think ‘I do not want to read the leaflet’,
so [adding visuals] makes [the leaflet] more fun to read.’’
In addition, participants thought that visuals could draw
attention to specific topics. By serving as a cue, a visual
could prove useful by highlighting topics that should not be
overlooked, including warnings. This way of using images
was also considered helpful by participants whose reading
levels do not allow them to read the text themselves, and
who could use visual cues to ask others to help read them
particular sections of text.
Comprehending, generating, acquiring stages
Quite a few participants also thought that more informative
images, such as pictograms, could provide a visual
overview of the leaflet to help get a first impression of the
information, and enable them to navigate the text and read
selectively. Pictograms could also help to understand or
even eliminate the need to read written information. This
was thought to make information in the leaflet quicker to
retrieve, clearer and easier to understand - especially since
some participants indicated that it is easier to extract
meaning from a visual than from a text.
According to a few participants, visuals could be used to
validate their understanding of text and could empower and
increase confidence. In this context, it was considered
helpful to have visuals that show required actions, for
example, a pictogram of how the medicine should be
administered. It was suggested by a participant that such
visuals could also be used to reassure children by showing
what will happen. Yet another participant mentioned that
adding visuals would make her feel safer, again in the
context of children and medication.
Some participants also saw a role for pictograms in
recalling previously acquired knowledge: ‘‘Then you
would not have to read the leaflet in its entirety, you would
have this visual language.’’ Many participants were
Uses for visuals in PILs as identified by low-literate participants
Make the leaflet look more appealing and inviting
Help navigate the leaflet to find relevant information
Help to highlight warnings
Serve as a tool to ask questions to caregivers
Explain and help understand what is written in text
Provide an overview of the information in the leaflet
Help to recall information
Preview what needs to be done in a visual instruction
Reassure care-receivers by showing what they can expect
Contribute to a clearer, easier and quicker to use, shorter leaflet
Enhance a feeling of confidence, empowerment and safety
confident in their ability to recall verbal information
provided by their pharmacist, but considered it useful to have
visuals for cued recognition. This was especially the case
for people who were mostly reliant on verbal information,
because ‘‘there is always a chance that you forget what they
The aim of this study was to gain insight into how people with
low literacy evaluate written drug information, and to
identify ways in which images could help them improve this
experience. We found that individuals with low literacy are
discouraged by the overall look of patient information, as
well as by its content, as relevant information is difficult to
find and to understand. These findings are concurrent with
previous research concerning patients’ experience with drug
information [2, 10, 34]. Although a printed leaflet is still the
preferred medium to receive medication instructions,
existing materials are unsuited, which makes patients with low
literacy reliant on other people, drug labels, or on online
sources of varying reliability.
People have a limited capacity for processing new
information, and different channels for processing words
and pictures . Low-literate people indicate that they
experience a high cognitive load when required to read
written drug information, which is reflected in their
comments about the time and effort it takes to read and process
the information - visuals may help to limit this load .
Low-literate people find visuals to be a useful
supplement for a variety of reasons. Images can provide a quick
overview of and context to the information in a leaflet, and
can facilitate understanding of what is written in text. In the
context of McGuire’s model of mass communication
(Table 5), and the corresponding stages that people
proceed through to reach successful persuasion, this translates
to that images can help to progress through the
‘comprehending’ phase (4). Several studies have shown that
images, and especially pictograms, can be an effective tool to
increase patients’ understanding of textual information
[13, 18, 37]. In particular, low-literate people are interested
in images that show exactly what they have to do, to
facilitate the generation of the cognitions (5) and acquire
the skills (6) necessary to take their medication as
In addition to enhance central processing, many
suggestions relate to the idea of visuals as peripheral cues
(e.g., to make the leaflet more appealing, or to attract
attention to the leaflet or particular topics) [38, 39]. In this
role, images can help the patient to successfully proceed
from the tuning in phase (1), to attending (2) and liking (3)
- essential to reach the comprehending (4) stage. This is
important given the finding that many people with low
literacy find it difficult to work up the motivation required
for central processing, or to ‘decipher’ the information. As
peripheral cues, images also increase the likelihood of
people with low elaboration to be persuaded by and agree
(7) with the message, and decide (10) to act upon it (11),
without central processing taking place [38, 39].
This, however, does not mean that purely decorative
images need to be added to patient information, as previous
research has shown that this can be experienced as
distracting . It is likely that appeal of the document can be
increased enough by providing structure and support in the
form of explanatory images that increase the readability of
the text and images that highlight important topics.
The latter, ‘flagging’ information, is an important
potential role for images, as one of the biggest concerns
of the participants was how difficult it is to find relevant
information in the leaflet – exactly why they were so
appreciative of headings in the text, a finding that is
supported by previous studies [41, 42]. In addition, one of
the ways in which low-literate people said to obtain
Table 5 Communication outputs that can be targeted by visuals
Outputs as described by McGuire
Illustration of a persuasive process to adhere to medication, taking place through the patient leaflet.
Exposure to the PIL
Paying attention to the PIL
Liking, maintaining interest in the PIL
Understanding the message in the PIL eg., ‘‘I should take my medication every day’’
‘‘I know what I can do to make sure I take my medication every day’’
‘‘I know how I can take my medication every day’’
‘‘I agree it would be good to take my medication as prescribed’’
‘‘I have stored in my memory that I want to take the medication every day’’
‘‘I remember this at relevant times’’
‘‘I am going to take my medication every day’’
‘‘I really do take my medication every day’’
‘‘I have integrated taking my medication into my life’’
‘‘Others should also take their medication as prescribed’’
information on their medicine was to ask a caregiver or
family member to read the PIL for them. In this way,
images that highlight can work empowering, by allowing
patients who cannot read to ask for specific information
from their healthcare provider or caregiver based on what
they can see in the pictogram.
Low-literate people also see a role for images to help
remember information (9) that has been communicated
previously. Many are dependent on information they
receive orally, and visual confirmation can help to enhance
their confidence in the knowledge they have.
Generalisations should be made with care, given the
qualitative nature of this study, the convenience
sampling, and the fact that the majority of the sample was
female. Social stigmas  may prevent participants
from being completely open about difficulties they
experience. However, the instructor’s presence during
the focus group sessions encouraged participants to
openly contribute to the discussion. Even if participants
were somewhat reserved in their answers, the results will
underestimate the problem rather than overestimate it,
and it is expected to have been of little influence on the
way people responded about possible uses for visuals.
Another limitation of the study is that in order to make
the topics under discussion more approachable, it was
necessary to show examples of both leaflets and visuals.
The selection of these materials may have influenced
how participants viewed the topic, so that they did not
have full creative freedom in their answers. However, in
every session it was attempted to start the conversation
as open as possible, so that the authors feel that showing
the examples was a necessary step to successfully
engage in a participatory design process with low-literate
People with low literacy experience barriers in
communication via written drug information early on in the
communication/persuasion process, i.e., at the stages of paying
attention to the leaflet and maintaining interest in the
message. These barriers can be lowered through the use of short,
structured textual explanations, supported by images. This
approach further has the potential to improve understanding
of information and to empower the target group of
lowliterate patients. The outcomes of this study confirm the roles
for images as described by EU-regulations on patient
leaflets, i.e. images to highlight topics, aid navigation and clarity
text (Article 62 of Directive 2001/83/EC), and suggest an
equally important role for images to lower the motivational
threshold for patients with low literacy to take interest in the
information. By honouring the input of the target group in
this very early stage of the design process, a resulting
visual/textual intervention is more likely to match the
information preferences and needs of people with low
literacy, and may even have the empowering effect that
participants of this study themselves describe.
Acknowledgments The authors would like to thank TaalPlusschool
ROC Mondriaan Den Haag and Voedselbank Haaglanden for their
help to reach the target group.
Funding No external funding was received for this study.
Open Access This article is distributed under the terms of the Creative
Commons Attribution 4.0 International License (http://creative
commons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
1. Wolf MS , Davis TC , Shrank W , Rapp DN , Bass PF , Connor UM , et al. To err is human: patient misinterpretations of prescription drug label instructions . Patient Educ Couns . 2007 ; 67 ( 3 ): 293 - 300 .
2. Koo MM , Krass I , Aslani P. Factors influencing consumer use of written drug information . Ann Pharmacother . 2003 ; 37 ( 2 ): 259 - 67 .
3. Davis TC , Wolf MS , Bass PF , Middlebrooks M , Kennen E , Baker DW , et al. Low literacy impairs comprehension of prescription drug warning labels . J Gen Int Med . 2006 ; 21 ( 8 ): 847 - 51 .
4. Kutner M , Greenberg E , Baer J. A first look at the literacy of America's adults in the 21st century . NCES 2006-470. National Center for Education Statistics . 2006 .
5. Lindquist LA , Go L , Fleisher J , Jain N , Friesema E , Baker DW. Relationship of health literacy to intentional and unintentional non-adherence of hospital discharge medications . J Gen Int Med . 2012 ; 27 ( 2 ): 173 - 8 .
6. Wolf MS , Davis TC , Osborn CY , Skripkauskas S , Bennett CL , Makoul G . Literacy, self-efficacy, and HIV medication adherence . Patient Educ Couns . 2007 ; 65 ( 2 ): 253 - 60 .
7. Leendertse AJ , Egberts AC , Stoker LJ , van den Bemt PM . Frequency of and risk factors for preventable medication-related hospital admissions in the Netherlands . Arch Int Med . 2008 ; 168 ( 17 ): 1890 - 6 .
8. Osterberg L , Blaschke T. Adherence to medication . N Engl J Med . 2005 ; 353 ( 5 ): 487 - 97 .
9. Kessels RP . Patients' memory for medical information . J R Soc Med . 2003 ; 96 ( 5 ): 219 - 22 .
10. Grime J , Blenkinsopp A , Raynor DK , Pollock K , Knapp P. The role and value of written information for patients about individual medicines: a systematic review . Health Expect . 2007 ; 10 ( 3 ): 286 - 98 .
11. Ngoh LN , Shepherd MD . Design, development, and evaluation of visual aids for communicating prescription drug instructions to nonliterate patients in rural Cameroon . Patient Educ Couns . 1997 ; 30 ( 3 ): 257 - 70 .
12. Braich PS , Almeida DR , Hollands S , Coleman MT. Effects of pictograms in educating 3 distinct low-literacy populations on the use of postoperative cataract medication . Can J Ophthalmol . 2011 ; 46 ( 3 ): 276 - 81 .
13. Dowse R , Ehlers M. Medicine labels incorporating pictograms: do they influence understanding and adherence? Patient Educ Couns . 2005 ; 58 ( 1 ): 63 - 70 .
14. Katz MG , Kripalani S , Weiss BD. Use of pictorial aids in medication instructions: a review of the literature . Am J Health Syst Pharm . 2006 ; 63 ( 23 ): 2391 - 8 .
15. Delp C , Jones J. Communicating information to patients: the use of cartoon illustrations to improve comprehension of instructions . Acad Emerg Med . 1996 ; 3 ( 3 ): 264 - 70 .
16. Houts PS , Bachrach R , Witmer JT , Tringali CA , Bucher JA , Localio RA . Using pictographs to enhance recall of spoken medical instructions . Patient Educ Couns . 1998 ; 35 ( 2 ): 83 - 8 .
17. Houts PS , Witmer JT , Egeth HE , Loscalzo MJ , Zabora JR . Using pictographs to enhance recall of spoken medical instructions II. Patient Educ Couns . 2001 ; 43 ( 3 ): 231 - 42 .
18. Thompson AE , Goldszmidt MA , Schwartz AJ , Bashook PG . A randomized trial of pictorial versus prose-based medication information pamphlets . Patient Educ Couns . 2010 ; 78 ( 3 ): 389 - 93 .
19. Wilby K , Marra CA , da Silva JH , Grubisic M , Harvard S , Lynd LD. Randomized controlled trial evaluating pictogram augmentation of HIV medication information . Ann Pharmacother . 2011 ; 45 ( 11 ): 1378 - 83 .
20. Morrow DG , Weiner M , Steinley D , Young J , Murray MD . Patients' health literacy and experience with instructions influence preferences for heart failure medication instructions . J Aging Health . 2007 ; 19 ( 4 ): 575 - 93 .
21. Morrow DG , Weiner M , Young J , Steinley D , Deer M , Murray MD . Improving medication knowledge among older adults with heart failure: a patient-centered approach to instruction design . Gerontologist . 2005 ; 45 ( 4 ): 545 - 52 .
22. Lambert SD , Loiselle CG . Combining individual interviews and focus groups to enhance data richness . J Adv Nurs . 2008 ; 62 ( 2 ): 228 - 37 .
23. Karwowski W. Ergonomics and human factors: the paradigms for science, engineering, design, technology and management of human-compatible systems . Ergonomics . 2005 ; 48 ( 5 ): 436 - 63 .
24. Sanders EBN , Stappers PJ . Co-creation and the new landscapes of design . Co-design . 2008 ; 4 ( 1 ): 5 - 18 .
25. Houts PS , Doak CC , Doak LG , Loscalzo MJ . The role of pictures in improving health communication: a review of research on attention , comprehension, recall, and adherence. Patient Educ Couns . 2006 ; 61 ( 2 ): 173 - 90 .
26. Corcoran N. Theories and models in communicating health messages. Communicating health: strategies for health promotion . London: Sage Publications Ltd ; 2007 . p. 5 - 31 .
27. Fransen M , Van Schaik T , Twickler T , Essink-Bot M. Applicability of internationally available health literacy measures in the Netherlands . J Health Commun . 2011 ; 16 (sup3): 134 - 49 .
28. Safeer RS , Keenan J. Health literacy: the gap between physicians and patients . Am Fam Phys . 2005 ; 72 ( 3 ): 463 - 8 .
29. Easton P , Entwistle VA , Williams B. Health in the'hidden population'of people with low literacy. A systematic review of the literature . BMC Public Health . 2010 ; 10 ( 1 ): 459 - 68 .
30. Expertgroep Doorlopende Leerlijnen Taal en Rekenen . Reference standards language and mathematics. Enschede: Ministry of OCW ; 2009 .
31. U.S. Pharmacopeial Convention. USP pictograms . http://www. usp. org/usp-healthcare-professionals/related-topics-resources/usppictograms . Accessed Sep 2016 .
32. NYU Langone Medical Center . HELPix. http://www.med.nyu. edu/helpix/. Accessed Sep 2016 .
33. Ritchie J , Spencer L , O'Connor W. Carrying out qualitative analysis . In: Lewis J , Ritchie J, editors. Qualitative research in practice. London: SAGE Publications ; 2003 .
34. Maat HP , Lentz L. Improving the usability of patient information leaflets . Patient Educ Couns . 2010 ; 80 ( 1 ): 113 - 9 .
35. Mayer RE , Moreno R. Nine ways to reduce cognitive load in multimedia learning . Educ Psychol . 2003 ; 38 ( 1 ): 43 - 52 .
36. Mayer RE . Multimedia learning . Psychol Learn Motiv . 2002 ; 41 : 85 - 139 .
37. Morrow DG , Hier CM , Menard WE , Leirer VO . Icons improve older and younger adults' comprehension of medication information . J Gerontol B Psychol Sci Soc Sci . 1998 ; 53 ( 4 ): P240 - 54 .
38. Chaiken S , Liberman A , Eagly AH . Heuristic and systematic information processing within and beyond the persuasion context . In: Ulenian JS, Bargh JA, editors. Unintended thought . New York : Guilford Press ; 1989 . p. 212 - 52 .
39. Petty R , Cacioppo JT . Communication and persuasion: central and peripheral routes to attitude change . Berlin: Springer; 2012 .
40. Griffin J , Wright P. Older readers can be distracted by embellishing graphics in text . Eur J Cogn Psychol . 2009 ; 21 ( 5 ): 740 - 57 .
41. Kools M , Ruiter RA , Van De Wiel MW , Kok G. The effects of headings in information mapping on search speed and evaluation of a brief health education text . J Inform Sci . 2008 ; 34 ( 6 ); 833 - 44 .
42. Hoffmann T , Worrall L. Designing effective written health education materials: considerations for health professionals . Disabil Rehabil . 2004 ; 26 ( 19 ): 1166 - 73 .
43. Easton P , Entwistle VA , Williams B. How the stigma of low literacy can impair patient-professional spoken interactions and affect health: insights from a qualitative investigation . BMC Health Serv Res . 2013 ; 13 ( 1 ): 319 .