Post on 15-Apr-2017
Web Accessibility and SEO A comparison of guidelines aiming to identify overlaps between web accessibility and SEO
Alexandre Amado de Castro
FCI – Faculty of Computing and Informatics
Mackenzie Presbyterian University
São Paulo, Brazil
alexandre.amado.castro@gmail.com
Alessandra Sutto Marucci
FCI – Faculty of Computing and Informatics
Mackenzie Presbyterian University
São Paulo, Brazil
alessandrasmarucci@gmail.com
Abstract—In a context where the Internet have been radically
overhauling the forms of communication and access to
information, two main concepts come to surface. In one hand, the
concept of Search Engine Optimization (SEO) aims to the
searching and finding of information ensuring that a site is
accessible to any given search engine. On the other hand, the
concept of web accessibility aims to the ability of using and
understanding the information found on the web ensuring that a
website is accessible to any given person. Therefore, both
concepts have accessibility as a goal, differentiating only the final
client: the search engine or the human user. To achieve this goal
there are several recommendations, techniques, orientations and
guidelines for both SEO and accessibility. This article aims to
investigate whether a site developed according to accessibility
guidelines can also be optimized for search engines. Through
literature review and analysis of selected websites, the results
show that there is a strong relationship between compliance with
accessibility guidelines and the ranking of a website in a search
engine and that many of the guidelines for both concepts overlap.
Keywords—Web accessibility, search engine optimization,
eMAG, WCAG.
I. INTRODUCTION
The evolution of the Internet has been radically overhauling
the forms of communication and access to information.
Concerning specifically to access to information, two concepts
emerge.
The first concept is the Search Engine Optimization (SEO),
which concerns to the search and location of information and
aims to guarantee that a website is available to search engines.
With the massive increase of information on the Internet,
search engines have evolved towards making the process of
finding information an easy task, while those responsible for
web pages strive to have their websites well ranked in these
search engines rankings, making use of SEO techniques.
Search engine optimization (SEO) refers to the process of
increasing the number of website visitors by achieving higher
ranks in the search results returned by a search engine. The
higher a website ranks in the results pages, the greater the
chance the users will visit the site [1].
The second concept refers to web accessibility, concerning
the ability to understand and use the information found on the
web and it aims to ensure that a website is accessible to any
individual. However, people with disabilities may have access
to information available on the internet impaired or prevented
if the web pages were not implemented following standards of
digital accessibility.
Web accessibility means that people with disabilities can
perceive, understand, navigate, and interact with the web, and
that they can contribute to the web [2].
Hence, both concepts have focus on accessibility. While
SEO techniques seek to make a site accessible to search
engines, web accessibility guidelines seek to make a site
accessible to all users.
Regarding the SEO, there are many recommendations and
techniques to make a website optimized for search engines.
Companies such as Moz and many others seek to determine
which are the most relevant factors in achieve good positioning
in search engines [3].
With the goal of designing a universally accessible web,
important legislative and non-governmental web
standardization and normalization initiatives have been
undertaken in many countries [3]. One of these initiatives, the
Web Accessibility Initiative (WAI) of the World Wide Web
Consortium (W3C), is responsible for the Web Content
Accessibility Guidelines (WCAG), which covers a wide range
of recommendations for making web content more accessible
[4]. In Brazil, the Electronic Government Accessibility Model
(eMAG) is a specialized version of the WCAG, focused on
digital content of the federal government.
Perhaps due to the fact that web accessibility and SEO
projects have generally been carried out by experts from
different fields and promoted in different ways and to different
sectors, each type of project has been understood as distinct
and undertaken independently from the other [3].
With so many recommendations, techniques, guidelines
and directives aimed at accessibility and at optimization for
search engines, being aware of every one of them and bringing
them together is not an easy task. Apply them effectively in
order to ensure an accessible website for both users and search
engines can slow down the development process, requiring
professionals that are more specialized, longer deadlines and
hence increased costs.
This article aims to investigate whether a site developed
according to accessibility guidelines can also be optimized for
search engines assessing thereby if the search for accessibility
is compatible with the search for relevance in the rankings of
search engines and if accessibility and SEO guidelines overlap
or contradict each other.
This research was done in two steps. In the first step, from a
literature review, the main web accessibility and SEO
guidelines were confronted by analyzing the points at which
they are similar, complement each other or clash. In the second
step, three websites were selected for analysis and proof of
concept in order to verify the accuracy of the analysis
conducted in the first step.
The rest of this paper is organized as follows. Section II
reviews relevant literature to this study and gives some
background material on past-related work. Section III describes
the methodology used. In section IV, theoretical and
experimental results are shown and discussed. Finally, some
concluding remarks and suggestions for future work are
provided in section V.
II. LITERATURE REVIEW
A. Web Accessibility
Web accessibility means that people with disabilities can
use the web properly. More specifically, web accessibility
means that people with disabilities can perceive, understand,
navigate, and interact with the web. Web accessibility
encompasses all disabilities that affect access to the web,
including visual, auditory, physical, speech, cognitive, and
neurological disabilities [5].
Web accessibility also benefits people without disabilities.
For example, a key principle of web accessibility is designing
websites and software that are flexible to meet different user
needs, preferences, and situations. This flexibility also benefits
people without disabilities in certain situations, such as people
using a slow Internet connection, people with "temporary
disabilities" such as a broken arm, and people with changing
abilities due to aging [2].
In order to eliminate accessibility barriers, legislative and
non-governmental web standardization and normalization
initiatives came up. Some of these initiatives, related to the
context of this study, are presented below.
1) Sections 504 and 508
The Rehabilitation Act of 1973 is an U.S. federal law,
which provides a wide range of services that secure an equal
playing field for individuals with disabilities. Sections 504 and
508 of the Rehabilitation Act have impact on web accessibility.
While section 504 provides the context of the law, section 508
provides the direction.
Section 504 of the Rehabilitation Act was the first civil
rights legislation in the United States designed to protect
individuals with disabilities from discrimination based on their
disability status [6].
Amended in 1998, section 508 bars the federal government
from procuring electronic and information technology goods
and services that are not fully accessible to those with
disabilities. This would include the services of web design
since the Internet was specifically mentioned. Section 508
provided the first-ever US federal accessibility standard for the
Internet [6].
2) Web Content Accessibility Guidelines (WCAG)
The World Wide Web Consortium (W3C) is an
international community whose mission is to lead the World
Wide Web to its full potential by developing protocols and
guidelines that ensure the long-term growth of the web [7].
Through its Web Accessibility Initiative (WAI), W3C has
developed standards, strategies, guidelines and resources in
order to promote web accessibility. One of these standards is
the Web Content Accessibility Guidelines (WCAG), currently
in 2.0 version and approved as an ISO standard (ISO/IEC
40500:2012).
WCAG 1.0, which became a W3C recommendation in
1999 [8], is organized around 14 guidelines that have
checkpoints, which are priority 1, 2, or 3. These checkpoints
are the basis for determining conformance to the WCAG 1.0
[9].
WCAG 2.0 followed WCAG 1.0 in 2008 [4]. WCAG 2.0 is
organized around 4 design principles of web accessibility. Each
principle has guidelines, and each guideline has testable
success criteria at level A, AA, or AAA. These success criteria
are the basis for determining conformance to the WCAG 2.0
[9]. The four principles of WCAG 2.0 are: perceivable, with 4
guidelines; operable, with 4 guidelines; understandable, with 3
guidelines; robust, with 1 guideline. A total of 12 guidelines
[4].
Although it is possible to conform either to WCAG 1.0 or
to WCAG 2.0 (or both), the W3C recommends the use of
WCAG 2.0 for new and updated content [4]. WCAG 2.0 was
developed to be testable and technique-independent. This
allows the guidelines to be used for emerging and future web
techniques [10]. WCAG 2.0 covers a wide range of
recommendations for making web content more accessible. Its
guidelines defines how to make web content accessible to
people with disabilities, including blindness and low vision,
deafness and hearing loss, learning disabilities, cognitive
limitations, limited movement, speech disabilities,
photosensitivity and combinations of these [4].
3) Electronic Government Accessibility Model (eMAG)
The Electronic Government Accessibility Model (eMAG,
from the Portuguese Modelo de Acessibilidade em Governo
Eletrônico) is a set of recommendations to be considered for
easy and standardized implementation of accessibility in
Brazilian government sites and portals [11].
Elaborated by the Electronic Government Department in
partnership with the Non-Governmental Organization
Acessibilidade Brasil, eMAG was developed in 2004 and is
grounded in the study of 14 existing digital accessibility
standards from other countries, including the United States
government’s Section 508, the Canadian CLF standards, the
Irish accessibility guidelines and documents from other
countries like Portugal and Spain. Furthermore, it was also
carried out a detailed analysis of the rules and checkpoints
from the international organization WAI/W3C, which are
found in the WCAG 1.0 [12].
The eMAG version 3.0 was released in 2011, based on
eMAG previous version, 2.0, supported by WCAG 2.0 and
new research in web accessibility.
Besides using WCAG as reference and being aligned with
the international recommendations, eMAG current version, 3.1,
was developed for local necessities, aiming to comply with
Brazilian priorities [12].
The eMAG version 3.1 contains 45 recommendations,
divided in 6 sections: markup, behaviour (Document Object
Model – DOM), content/information, presentation/design,
multimedia and form.
B. Search Engine Optimization (SEO)
Search Engine Optimization (SEO) is the science of
customizing your website elements to achieve the best possible
ranking at search engine results [13].
On the back end, a search engine is a piece of software that
uses algorithms to find and collect information about web
pages. On the front end, the software has a user interface where
users enter a search term in an attempt to find specific
information [13].
Since web searchers are free to use any of the many
available search engines on the web to find what they are
seeking, the burden is on the search engines to develop a
relevant, fast, and fresh search experience [1]. Google is the
world's most popular search engine, with a market share of
62.3 percent as of March 2015 [14].
Search has penetrated the very fabric of global society. The
way people work, play, shop, research, and interact has
changed forever. Organizations, as well as individuals, need to
have a presence on the web, and they need search engines to
bring them web traffic. Therefore, both, SEO practitioners and
search engines, have a common goal of providing searchers
with results that are relevant to their queries [1].
SEO factors are difficult to enumerate, as search engines do
not reveal the specific factors used when determining a website
ranking. Search engines constantly work to improve their
ranking algorithms and, as a result, the calculated relevance of
web pages has been observed to vary over time, due to changes
in the relative weights assigned to individual SEO factors, as
well as the incorporation of new factors and the elimination or
modification of others [3].
C. Evaluation Tools
There are a number of tools used to ensure that a website
meets established accessibility standards or to get reports
regarding a website SEO performance. Some related concepts
as well as the tools selected for this study are presented below.
1) Web Content Accessibility Evaluation Tools
Web accessibility evaluation tools are software programs or
online services that help to determine if web content meets
accessibility guidelines [15].
W3C has a list of several tools for accessibility evaluation.
These tools are classified based on guidelines supported,
operating systems, license types, web techniques, report
formats, browsers support, and languages [10].
For this article the WAVE (Web Accessibility Versatile
Evaluator) by WebAIM, present on the W3C Web
Accessibility Evaluation Tools List [15], has been selected.
Although only a human can determine true accessibility,
WAVE can help evaluating the accessibility of a website
checking it against WCAG 2.0 and Section 508 guidelines
[16].
2) Search Engine Optimization Tools
The expert SEO practitioner knows how important it is to
establish quantifiable goals and demonstrate results. Search
engine optimization tools can provide a rich array of data that
is invaluable to the SEO process. Numerous tools are available
to aid in this process. They allow monitoring a website,
providing insight into SEO progress and new ideas on how to
adapt a strategy to get better results [1].
SEO Analyzer Check from SEOCentro has been chosen for
this study since it is a free and online tool with very detailed
reports. SEO Analyzer Check gives an in-depth analysis of
web pages on-site and off-site SEO ranking on a page-by-page
basis [17].
D. Previous Research
The available literature provides many studies that analyze
both the accessibility guidelines and SEO factors separately.
Despite this, however, very little has been written about the
overlaps between SEO techniques and web accessibility
guidelines [3].
Moreno and Martinez [3] attempted to fill this gap in the
literature. They presented the overlaps between WCAG 2.0 and
SEO on-page factors in a summary based on WCAG
documentation and Moz [18], a non-academic SEO resource.
Based on the analysis of the summarized resources, the authors
offered some guidelines for web professionals.
A WAI document [19] that describes the financial factors in
developing a customized web accessibility business case for a
specific organization, mentioned that one of the benefits of web
accessibility is that it increases findability with search engine
optimization.
Accessibility improving search engine optimization is also
mentioned on another WAI document [20] that presents an
article detailing many of the overlaps between accessibility
guidelines and best practice for SEO and a guide of the
applicability of the WCAG 2.0 techniques documents to SEO.
Although based primarily on eMAG 3.1 instead of WCAG
2.0, the present study is closely related to the approach
proposed by Moreno and Martinez [3]. But it gives a step
forward towards presenting an analysis of selected websites
based on the guidelines and techniques studied to provide
evidence that the overlapping factors not only ensure the
accessibility of a website for all users, but also are useful for
the optimization of the website’s search engine ranking.
III. METHODOLOGY
A. Literature Review
In the first step of this study a literature review was done.
The first document studied was eMAG 3.1, which provided the
basis for drawing up an accessibility guidelines list consistent
with the goal of this article.
The criteria for selecting the guidelines of that list
considered the correlation of each guideline with SEO
techniques. Therefore, some guidelines have been discarded
since they clearly do not influence, neither positively nor
negatively, the positioning of a website in search engines’
ranking. This applies, for example, to eMAG 3.1
recommendation 4.1 – provide minimum contrast between
background and foreground – discarded for that reason.
Considering this criteria, from the 45 eMAG 3.1
recommendations, 22 were selected for the list, as presented in
Table I.
TABLE I. EMAG 3.1 SELECTED RECOMMENDATIONS
Section Recommendation Selected
Mar
kup
1.1 – Respect web standards Yes
1.2 – Arrange the HTML logically and semantically Yes
1.3 – Properly use the header levels Yes
1.4 – Sort logically and intuitively reading and tab No
1.5 – Provide anchor text for direct access to content blocks No
1.6 – Do not use tables for layout Yes
1.7 – Separate adjacent links No
1.8 – Divide the information areas Yes
1.9 – Do not open new instances without the user’s request No
Beh
avio
ur
(Docu
men
t
Obje
ct M
odel
– D
OM
) 2.1 – Make all functionality available from a keyboard Yes
2.2 – Ensure that programmable objects are accessible Yes
2.3 – Do not create periodically auto-refreshing pages No
2.4 – Do not redirect pages automatically No
2.5 – Provide alternative for adjusting time limit No
2.6 – Do not include situations with screen flickering No
2.7 – Ensure user control of time-sensitive content changes No
Conte
nt/
Info
rmat
ion
3.1 – Identify the primary natural language of the page Yes
3.2 – Inform language change in the content Yes
3.3 – Provide an informative and descriptive title for each page Yes
3.4 – Inform the user of his location on the page Yes
3.5 – Clearly and briefly describe each link Yes
3.6 – Provide text alternatives for images Yes
3.7 – Make use of accessible image maps No
3.8 – Provide documents in accessible formats No
3.9 – Provide proper titles and summaries for tables Yes
3.10 – Associate data cells with header cells Yes
3.11 – Ensure the reading and understanding of the information No
3.12 – Provide an explanation for acronyms, abbreviations and unusual words Yes
Pre
senta
tion/
Des
ign
4.1 – Provide minimum contrast between background and foreground No
4.2 – Do not use only colour or other sensory characteristics to differentiate elements No
4.3 – Allow resizing without loss of functionality Yes
4.4 – Ensure that the keyboard focus indicator is visible No
Mult
imed
ia 5.1 – Provide alternative for video Yes
5.2 – Provide alternative for audio Yes
5.3 – Provide audio description for pre-recorded video No
5.4 – Provide audio control for sound No
5.5 – Provide animation control No
Form
6.1 – Provide text alternative for form image buttons Yes
6.2 – Associate text labels with form controls Yes
6.3 – Ensure a logical navigation order No
6.4 – Do not automatically cause a change of context No
6.5 – Provide instructions for data input No
6.6 – Identify and describe input errors and confirm the transmission of information No
6.7 – Group form fields No
6.8 – Provide specific security strategies instead of CAPTCHA Yes
In addition to the accessibility recommendations, eMAG
3.1 quotes some bad practices that should be avoided because
they are considered obstacles to the access of people with
disabilities as well as for access by mobile devices. Two of
these practices were selected and stated as guidelines for
incrementing the list: do not use Flash animations and
applications and avoid deprecated features of W3C
technologies.
Afterwards, a study of WCAG 2.0 and WCAG 1.0 was
conducted, which did not result in the inclusion of new
guidelines to the list, because reading these documents it was
possible to notice that the guidelines presented in WCAG
overlap with eMAG 3.1 recommendations.
Consequently, at the end of the literature review, the list
was completed with 24 recommendations selected from eMAG
3.1. Table II presents eMAG 3.1 selected recommendations
and its correlations with WCAG 1.0 checkpoints and WCAG
2.0 success criteria.
From this list, an investigation in the literature on search
engine optimization was conducted, searching for techniques
correlated to each of the accessibility guidelines. It was then
possible to establish the relationship between the selected
accessibility guidelines and SEO techniques, highlighting
points of similarity, complement or conflict between them.
TABLE II. EMAG 3.1 SELECTED RECOMMENDATIONS AND ITS CORRELATIONS WITH WCAG 1.0 AND WCAG 2.0
Guideline eMAG 3.1
recommendation
WCAG 1.0
checkpoint
WCAG 2.0
success criteria
1 Respect web standards 1.1 3.3 4.1.1
4.1.2
2 Arrange the HTML logically and semantically 1.2
3.1
6.1
11.1
1.3.1
3 Properly use the header levels 1.3 3.5 1.3.1
2.4.10
4 Do not use tables for layout 1.6 5.3
5.4
1.3.1
(H51)
5 Divide the information areas 1.8 13.4 3.2.3
(G61)
6 Make all functionality available from a keyboard 2.1 8.1 2.1.1
2.1.2
7 Ensure that programmable objects are accessible 2.2 8.1 2.1.1
2.1.2
8 Identify the primary natural language of the page 3.1 4.3 3.1.1
9 Inform language change in the content 3.2 4.1 3.1.2
10 Provide an informative and descriptive title for each page 3.3 - 2.4.2
11 Inform the user of his location on the page 3.4 - 2.4.8
12 Clearly and briefly describe each link 3.5 13.1 2.4.4
2.4.9
13 Provide text alternatives for images 3.6 1.1 1.1.1
(G95)
14 Provide proper titles and summaries for tables 3.9 5.5 1.3.1
(H39 and H73)
15 Associate data cells with header cells 3.10 5.1
5.2
1.3.1
(H43 and H63)
16 Provide an explanation for acronyms, abbreviations and unusual words 3.12 4.2 3.1.3
3.1.4
17 Allow resizing without loss of functionality 4.3 - 1.4.4
18 Provide alternative for video 5.1
1.1
1.3
1.4
1.2.1
1.2.2
1.2.6
1.2.8
19 Provide alternative for audio 5.2 1.1
1.4
1.2.1
1.2.2
1.2.6
20 Provide text alternative for form image buttons 6.1 1.1 1.1.1
21 Associate text labels with form controls 6.2 10.2
12.4
1.3.1
(H44)
22 Provide specific security strategies instead of CAPTCHA 6.8 - 1.1.1
(G143 and G144)
23 Do not use Flash animations and applications bad practice - -
24 Avoid deprecated features of W3C technologies bad practice 11.2 -
B. Selected Websites Analysis
In second step of this study, three types of sites were
chosen for analysis. The first type of site has an exclusive focus
on web accessibility. The second one is only concerned with
SEO. The last type of site uses the guidelines presented here
and splits its focus between web accessibility and SEO. For
each of these types, a site was selected for analysis.
The eMAG website has been selected for the web
accessibility focused type of site. Since it is a Brazilian
government website, it needs to implement all the eMAG
guidelines in full.
For the SEO focused website, the news website from the
biggest Brazilian portal has been selected. With 7.4 billion
monthly page views, UOL (Universo Online) was the perfect
highly efficient in SEO candidate [21].
Finding the shared focus type of website was the hardest of
the three. One of the fittest candidates was WebAIM (Web
Accessibility in Mind), which is the website of a non-profit
organization based at the Center for Person with Disabilities at
Utah University. WebAIM has provided comprehensive web
accessibility solutions since 1999 and its website is full of
information related to web accessibility [22]. As any website
for sharing information and service providing, it tries to
achieve high ranking in search engines. Furthermore, since it is
a website for web accessibility content, it applies WCAG 2.0 in
full.
Once the three websites were selected, it was possible to
run tests using evaluation tools to determine the web
accessibility and SEO conformity of these sites. In order to do
that, two evaluation tools have been selected, one for SEO and
another one for web accessibility.
SEO Analyzer Check from SEOCentro has been selected
for SEO analysis because it checks the website against the
selected recommendations presented in this article and other
SEO-specific techniques. Furthermore, it is free, online and
provides very detailed reports. The reports include features,
warnings, errors, social media presence, keywords and an SEO
ranking, which goes from 0 to 100.
WAVE was the selected evaluation tool for web
accessibility analysis because it is one of the tools presented in
W3C Web Accessibility Evaluation List and it can help
evaluating the accessibility of a website checking it against
WCAG 2.0 and Section 508 guidelines.
With the results of the tests, the relationship between web
accessibility guidelines and SEO techniques was established
and analyzed.
IV. RESULTS AND DISCUSSIONS
The results and discussions will be about the relationship
between web accessibility guidelines and SEO techniques and
about the analysis of the selected websites.
A. The Relationship between Web Accessibility and SEO
During literature review, as described in methodology, a
list of 24 accessibility guidelines was elaborated. These
guidelines were confronted with SEO techniques. From this
comparison, it was possible to establish the relationship
between web accessibility guidelines and SEO techniques,
highlighting points of similarity, complement or conflict
between them. This relationship is presented below in the form
of topics, where each topic corresponds to one of the 24
guidelines from the list presented in Table II.
1) Respect Web Standards
Web standards are W3C recommendations intended to
guide developers through the web accessibility best practices
[12]. As presented in Table II, eMAG recommendation 1.1,
WCAG 1.0 checkpoint 3.3 and WCAG 2.0 4.1.1 and 4.1.2
success criteria, all address to these web standards. One of
them is layer segmentation.
The logical layers should be separated according to the
purpose they were developed for. So, for the content layer,
markup languages should be used, such as HTML. For the
content visual presentation layer, CSS style sheets should be
used. As for the elements behaviour layer, JavaScript
languages and object models are used [12].
Using table-less CSS stored in external files, keeping
JavaScript calls external and separating the content layer from
the presentation layer also provide some indirect SEO benefits,
since keeping file size low means faster load times, lower
abandonment rates and a higher probability of the page being
fully read and more frequently linked to [1].
2) Arrange the HTML Logically and Semantically
The organization of HTML code in a logical and semantic
way and the use of each HTML element for the purpose it was
created is addressed by eMAG recommendation 1.2, WCAG
1.0 checkpoints 3.1, 6.1 and 11.1 and by WCAG 2.0 success
criteria 1.3.1, as presented in Table II.
The search engines face countless technical challenges in
understanding a website. Crawlers are not able to perceive web
pages in the way humans do, and thus significant limitations
for both accessibility and indexing exist. A logical and properly
constructed website architecture can help overcome these
issues and bring great benefits in search traffic and usability
[1].
3) Properly Use the Header Levels
The correct utilization of the header levels (HTML
elements from H1 to H6), in order to organize the importance
and subordination order of the contents, providing an easier
read and comprehension, is addressed by eMAG
recommendation 1.3, WCAG 1.0 checkpoint 3.5 and by
WCAG 2.0 success criteria 1.3.1 and 2.4.10, as presented in
Table II.
This web accessibility guideline is also an SEO technique.
The search engines have shown a slight preference for
keywords appearing in heading tags, notably the <h1> tag
(which is the most important of these to employ correctly) [1].
4) Do Not Use Tables for Layout
The use of tables strictly for tabular data and not for layout
purposes is addressed by eMAG recommendation 1.6, WCAG
1.0 checkpoints 5.3 and 5.4 and WCAG 2.0 success criteria
1.3.1 (technique H51), as presented in Table II.
SEO techniques reinforce this web accessibility guideline.
DIV-based layouts are search engine friendly because most of
the layout related definitions exist in a separated CSS file and
the main file is rendered quite light [23].
5) Divide the Information Areas
Information areas should be divided into manageable
groups. The most common divisions are "top", "content",
"menu" and "footer". However, it is important that the various
pages of the same website have the same consistent and
systematic presentation style, making it a structure pattern, so
that the user became quickly familiar with this structure [12].
To do this, structural elements of HTML, such as <header>,
<nav>, <section>, <article>, <aside> and <footer> can be used.
That is addressed by eMAG recommendation 1.8, WCAG 1.0
checkpoint 13.4 and WCAG 2.0 success criteria 3.2.3
(technique G61), as presented in Table II.
There are many reasons to believe that search engines are
applying page segmentation. The <header> tag gives a lot of
flexibility because is very similar to the <h1> tag, but it can
contain whole paragraphs of text, hard-coded links (which is
very significant for SEO) and any other kind of relevant info.
Navigation is one of the important factors for SEO, and
everything that eases navigation, such as the <nav> tag, is
welcome. The <section> and <article> tags are also good
additions from an SEO point of view, because they can be used
to identify separated sections on a page and separated entries in
an online publication, respectively. This makes the HTML
code cleaner because it reduces the need to use <div> tags and
search engines put more weight on the text inside the <section>
and <article> tags as compared to the content on other parts of
the page [24].
6) Make All Functionality Available From a Keyboard
According to eMAG recommendation 2.1, WCAG 1.0
checkpoint 8.1 and WCAG 2.0 success criteria 2.1.1 and 2.1.2,
as presented in Table II, all functionality of the content
developed using scripting languages (such as JavaScript)
should be operable through a keyboard interface [12].
In general, search engines only try to interpret any
JavaScript that may be present on a web page in a limited way
[1]. Therefore, it does not matter to SEO if all script
functionality of the content is operable through a keyboard
interface, since search engines are able to read plain HTML
[25].
7) Ensure That Programmable Objects Are Accessible
In addition to providing use by keyboard, strategies should
be adopted in order to provide access to programmable objects
to everyone, regardless of the device used. One of these
strategies is the <noscript> tag, which can be used to display
content in browsers that do not support scripts or who have the
script disabled [12]. These issues are addressed by eMAG
recommendation 2.2, WCAG 1.0 checkpoint 8.1 and WCAG
2.0 success criteria 2.1.1 and 2.1.2, as presented in Table II.
The <noscript> tag was originally designed to be a
legitimate tactic that would be acceptable by the search engines
as a way to accommodate older browsers or people with
special needs. However, many sites have used this code to trick
search engine spiders. Anyway, if the intent is to provide all
users with a positive experience while visiting a site, the
<noscript> tag should be used to accurately represent the
content of programmatic objects. Search engines read the
<noscript> tag and see it as information about the web page
[1].
8) Identify the Primary Natural Language of the Page
According to eMAG recommendation 3.1, WCAG 1.0
checkpoint 4.3 and WCAG 2.0 success criteria 3.1.1, as
presented in Table II, it is necessary to identify the primary
natural language of a website through the “lang” HTML
attribute, which must be declared on every page [12].
Language recognition by the search engines is important
because, if a website is in a specific language, it may rank very
well in a certain local Google [26]. Google does not trust the
page-level “lang” attribute, but that does not mean that other
search engines do not use it. And at the very least, if the page-
level “lang” attribute corresponds to Google’s “best guess”,
then it will provide it with the confirmation that it is indeed in
that particular language [27].
9) Inform Language Change in the Content
As presented in Table II, according to eMAG
recommendation 3.2, WCAG 1.0 checkpoint 4.1 and WCAG
2.0 success criteria 3.1.2, if any element on a page has content
in a language other than the principal, it must be identified
using the “lang” attribute, except for proper names or technical
terms that can be comprehended within context [12].
Incorrect language recognition by a search engine will
imply that a website will never top in the search results. So the
text-level "lang" attribute must be used when some text is
inserted in a different language, making sure that it corresponds
to the correct language [27].
10) Provide an Informative and Descriptive Title for Each
Page
As presented in Table II, eMAG recommendation 3.3 and
WCAG 2.0 success criteria 2.4.2 state that page title, provided
by the <title> tag, must be informative and descriptive and
should represent the main content of the page [12].
For keyword placement, title tags are the most critical
element for search engine relevance. The <title> tag is in the
<head> section of an HTML document and it is the only piece
of meta information about a page that influences relevancy and
ranking. This shows that for SEO is also important to make
sure the <title> tag on each page of the site is unique and
descriptive [1].
11) Inform the User of his Location on the Page
According to eMAG recommendation 3.4 and WCAG 2.0
success criteria 2.4.8, as presented in Table II, information
about the user's location within a set of web pages must be
provided. Breadcrumb navigation can be used for that. It
consists on navigable links in the form of hierarchical lists that
let the user know the path covered to get to the current page
[12].
For search engines, the navigation structure helps their
crawlers determine what pages are the most important on a
website, and it helps them establish the relevance of the pages
on a site to specific topics. Breadcrumb navigation is
encouraged by SEO and the anchor text in it must be keyword-
rich, which is helpful to both users and search engines [1].
12) Clearly and Briefly Describe Each Link
The eMAG recommendation 3.5, WCAG 1.0 checkpoint
13.1 and WCAG 2.0 success criteria 2.4.4 and 2.4.9, as
presented in Table II, address the clear identification of each
link target.
Search engines use anchor text (the actual text part of a
link, usually underlined) as an important ranking factor
because it helps them determine the relevancy of the referring
site and the link to the content on the landing page. Google
pays particular attention to the text used in a hyperlink and
associates the keywords contained in the anchor text to the
page being linked to. If anchor text is keyword-rich (with
keywords relevant to the targeted search terms), it will do more
for rankings in the search engines than if the link is not
keyword-rich [1].
13) Provide Text Alternatives for Images
As presented in Table II, eMAG recommendation 3.6,
WCAG 1.0 checkpoint 1.1 and WCAG 2.0 success criteria
1.1.1 (technique G95) address the need to provide a description
for the page images, making use of “alt” attribute [12].
This technique is also relevant for SEO because
incorporation of images on web pages can substantively enrich
the user experience, but the search engines cannot read the
images directly. One of the elements that can be used to give
the engines context for images is the "alt" attribute, where more
information about what is in the image can be provided and
where targeted keywords can be used [1].
This usage of the alt attribute permits to reinforce the major
keyword themes of the page. This is particularly useful if to
rank in image search is a goal. It is also important to make sure
the alt text reflect the content of the picture and do not
artificially emphasize keywords unrelated to the image (even if
they are related to the page) [1].
14) Provide Proper Titles and Summaries for Tables
The eMAG recommendation 3.9, WCAG 1.0 checkpoint
5.5 and WCAG 2.0 success criteria 1.3.1 (techniques H39 and
H73), as presented in Table II, address the use of the element
“caption”, which defines the title of a table, and the use of the
attribute “summary”, which provides a summary of the data
presented [12].
Using table tags like <caption>, that are already a part of
the HTML specification, is also a way of making tables more
search engine friendly. This tag can be used to give both users
and search engines more information about the content of
tables, improving document’s semantics and helping search
engines better understand what a given document is all about
[28].
15) Associate Data Cells with Header Cells
The eMAG recommendation 3.10, WCAG 1.0 checkpoints
5.1 and 5.2 and WCAG 2.0 success criteria 1.3.1 (techniques
H43 and H63), as presented in Table II, address the proper use
of elements like “th”, “td”, “thead”, “tbody” and “tfoot” in
order to provide more accessible data tables. In addition, they
cover the use of attributes like “id", "headers”, “scope” and
“col” in more complex tables [12].
SEO also recommends the use of these elements and
attributes to build more robust tables and to provide some
useful semantic information to search engines. None of them
has the means to alter the website rankings in search engines,
but the way data is laid inside these tags may affect how search
bots will read the data [29].
16) Provide an Explanation for Acronyms, Abbreviations
and Unusual Words
The necessity of providing explanation for acronyms,
abbreviations and unusual words is addressed by eMAG
recommendation 3.12, WCAG 1.0 checkpoint 4.2 and WCAG
2.0 success criteria 3.1.3 and 3.1.4, as presented in Table II.
From SEO perspective, the abbreviation tag (<abbr>)
should be used to indicate search engines more about the
subject matter of a web page. Marking up abbreviations gives
useful information to search engines and it helps them
differentiate similar themes [30].
17) Allow Resizing Without Loss of Functionality
As presented in Table II, eMAG recommendation 4.3 and
WCAG 2.0 success criteria 1.4.4 cover the resizing of the page
without loss of content or functionality and the responsive
design as an approach for providing the same content to
different screen resolutions.
Google has favoritism towards responsive design for a few
reasons. One is its ability to use a single URL for a website,
making it easier to link and share content with other sites.
Another reason is responsive design also makes it easier for
Google to crawl and index sites as opposed to crawling mobile-
optimized websites, which use individual URLs for their
desktop, tablet and mobile phone versions, causing URL
redirection. Unlike mobile-optimized websites, responsive
websites have the advantage of avoiding duplicate content.
This prevents Google spiders from being confused and
penalizing a website for duplicate content [31].
18) Provide Alternative for Video
Accessible alternatives for videos such as subtitles, audio,
text and sign language are addressed by eMAG
recommendation 5.1, WCAG 1.0 checkpoints 1.1, 1.3 and 1.4
and WCAG 2.0 success criteria 1.2.1, 1.2.2, 1.2.6 and 1.2.8, as
presented in Table II.
This is also relevant from an SEO perspective, since video
search engines have not yet been able to look inside the videos
to tell what their content is from a human “eye” perspective.
For that reason, it rely on other on-page factors, the metadata
within the video file itself, inbound links and anchor text to
determine what a video is about [1].
19) Provide Alternative for Audio
Accessible alternatives for audio such as text and sign
language are addressed by eMAG recommendation 5.2,
WCAG 1.0 checkpoints 1.1 and 1.4 and WCAG 2.0 success
criteria 1.2.1, 1.2.2 and 1.2.6, as presented in Table II.
From SEO perspective, these alternatives are also important
since search engines cannot easily understand words spoken in
an audio file. In the past few years, a number of companies
offering transcription services have cropped up, providing
automated text creation for the words spoken in audio or video
files. Providing these transcripts on rich media pages makes
your content accessible to search engines and findable by
keyword-searching visitors [1].
20) Provide Text Alternative for Form Image Buttons
Creating text alternatives for image buttons using “alt” and
“value” attributes is addressed by eMAG recommendation 6.1,
WCAG 1.0 checkpoint 1.1 and WCAG 2.0 success criteria
1.1.1, as presented in Table II.
As mentioned previously, the search engines face
challenges with identifying images from a relevance
perspective. Using alt attributes, originally created as metadata
for markup and an accessibility tag for vision-impaired users, is
a good way to present at least some text content to the engines
when displaying images or embedded non-text content [1].
21) Associate Text Labels with Form Controls
According to eMAG recommendation 6.2, WCAG 1.0
checkpoints 10.2 and 12.4 and WCAG 2.0 success criteria
1.3.1 (technique H44), as presented in Table II, text labels must
be associated with their corresponding form controls through
the attributes "for" and "id", both with the same value [11].
From an SEO point of view, this guideline is not relevant
because many form elements do not have an influence on
search engine algorithms. In addition, forms are supposed to be
sent using encryption and secured connections (https). If the
forms are on a secure page, optimizing them for search engines
will not matter since you should not even have https pages
indexed [33].
22) Provide Specific Security Strategies Instead of
CAPTCHA
As presented in Table II, eMAG recommendation 6.8 and
WCAG 2.0 success criteria 1.1.1 (techniques G143 and G144)
propose replacing CAPTCHA by a combination of different
strategies. CAPTCHA (Completely Automated Public Turing
Test to Tell Computers and Humans Apart) is a device used to
avoid spam robots and other software from gaining access to a
site. These usually involve visual or auditory tasks that are
beyond the current capabilities of web robots [33].
An alternate version of CAPTCHA is also important from
an SEO perspective, since password protection of any kind will
effectively prevent any search engines from accessing content,
as will any form of human-verification requirements, such as
CAPTCHAs. Major search engines will not try to guess
passwords or bypass these systems [1].
23) Do Not Use Flash Animations and Applications
The eMAG 3.1 discourages the use of animations and
applications in Flash in the development of websites and
electronic services of the Brazilian federal government because
this technology offers accessibility barriers for people with
disabilities and for mobile devices [12].
For SEO purposes, navigation in Flash is also a practice
that is not recommended, since search engines often cannot see
links and content implemented using this technology. If the
navigation is in Flash, should be considered showing search
engines a version of the site that has spiderable, crawlable
content in HTML [1].
24) Avoid Deprecated Features of W3C Technologies
The eMAG 3.1 recommends avoiding deprecated features
of W3C technologies – like frame, applet, blink, marquee,
basefont, center, dir, align, font, isindex, menu, strike, u, b, etc
– in development of the Brazilian government websites, since it
considers that the use of these features brings on negative
impact to user experience [12]. As presented in Table II,
WCAG 1.0 checkpoint 11.2 also addresses this issue.
In terms of SEO, deprecated tags have little or no influence
at all. For example, "center" tag it is purely a design tag and
"dir" and “font” tags has no SEO influence [34]. Using the
"frame" tag is a very bad design choice for building web pages.
This obsolete technique cloaks the real pages on a website by
using them as parts of other pages, usually the home page. As a
result, search engines may see the home page as empty and
may refuse to index the content on the website at all [35].
After reviewing the 24 accessibility guidelines selected, it
was observed that 22 of them overlap SEO techniques and
favor, when implemented, the positioning of a website in
search engines rankings.
Two guidelines showed up not being relevant from an SEO
perspective and therefore its implementation does not optimize
a website to search engines: make all functionality available
from a keyboard and associate text labels with form controls.
Finally, none of the 24 selected guidelines contradicts the
SEO techniques.
B. Selected Websites Analysis
As previously described in methodology, three websites
were selected for this step of the study: eMAG, UOL and
WebAIM. Each one of them was submitted to two selected
evaluation tools: WAVE for web accessibility analysis and
SEO Analyzer Check for SEO analysis.
Web accessibility analysis was the first to be accomplished.
For that it was necessary to capture the URL (Uniform
Resource Locator) for each selected website:
http://emag.governoeletronico.gov.br/, from eMAG.
http://noticias.uol.com.br/, from UOL.
http://webaim.org/, from WebAIM.
These URLs were then provided as input for WAVE, which
compared the websites pointing errors, alerts and properly
implemented accessibility recommendations, named as
“features”. The results, presented in Fig. 1, demonstrate that
eMAG and WebAIM had no accessibility errors, while UOL
had 17.
0
50
100
150
eMAG UOL WebAIM
Accessibilility Analysis Comparision
Errors Alerts Features
Fig. 1. Accessibility analysis comparison.
Since UOL website is SEO focused, it was expected that it
would present some accessibility errors. The same way, it was
also expected that eMAG website, which has an exclusive
focus on web accessibility, would present no errors. Regarding
WebAIM website, which splits its focus between web
accessibility and SEO, some accessibility error would have
been acceptable, but none were found.
Most of the accessibility errors displayed for UOL website
in Fig. 1 are related to missing alternative text for images and
missing forms labels.
As mentioned in the first step of this study results,
providing text alternatives for images is relevant for both web
accessibility and SEO, since it has a huge importance in
transmitting information. Without it, screen readers for people
with visual disabilities and search engine crawlers cannot
understand images meaning.
The missing labels make it impossible for the screen reader
users to fulfil the form. Nevertheless, as presented in the first
step of this study results, associating text labels with form
controls showed up not being relevant from an SEO
perspective. This might be the reason why UOL, an SEO
focused website, choose not implementing it.
The alerts shown in Fig. 1 are related to redundant
alternative texts, links and text titles, very small texts (harder to
read) and too long alternative texts.
The WebAIM website is smaller than the other two selected
websites, because its content is divided in several pages and
only one page could have been selected for analysis. However,
it does not represent a problem for the analysis, since what
matters for the evaluation tool is the quality of content, not its
size. Even if more than one page of the WebAIM website is
analyzed through WAVE, it always presents the same results
pattern. To demonstrate that, three WebAIM pages were
selected and submitted to WAVE:
Home: http://webaim.org/
Introduction: http://webaim.org/intro/
Blog: http://webaim.org/blog/
Figure 2 presents the results, where is possible to notice the
pattern repetition, since in none of the pages accessibility errors
are found. The alerts and features vary according to the page
size.
0
5
10
15
20
25
30
Home Introduction Blog
WebAIM PagesAccessibilility Analysis Comparision
Errors Alerts Features
Fig. 2. WebAIM pages accessibility analysis comparison.
Afterwards, the SEO analysis was made providing the
URLs of the selected websites as input for the SEO Analyzer
Check, which compared the websites pointing errors, warnings
and successfully implemented SEO techniques, named as
“passed”.
The results, presented in Fig. 3, demonstrate that eMAG
website had the higher number of SEO errors, followed by
UOL and WebAIM websites.
0
5
10
15
eMAG UOL WebAIM
SEO Analysis Comparision
Errors Warnings Passed
Fig. 3. SEO analysis comparison.
The errors found on eMAG are related to missing page
description, content size being bigger than 500kb and low
presence on social networks. None of these SEO issues are
directly related to accessibility guidelines, therefore it was
expected that eMAG website, which is fully focused on
accessibility, could present this kind of errors.
UOL errors are related to content size being bigger than
500kb, mostly because of news images, and page title being
bigger than 60 characters. Moreover, UOL is warned because
several images do not have “alt” attribute, used to provide
alternative text to images, a problem also reported by the web
accessibility evaluation tool, since it is related to an
accessibility guideline that overlaps an SEO technique.
Finally, WebAIM’s only error is missing page description.
Since eMAG website is web accessibility focused, it was
expected that it would present more SEO errors than the other
two websites. However, a closer look at the results reveals that
UOL website, which is SEO focused, showed nearly the same
amount of errors. This demonstrates that a site developed
according to accessibility guidelines, with no concern for SEO,
have also a good SEO conformance.
Analyzing the error report is possible to understand that
social networking presence is of major importance for SEO.
Figures 4, 5 and 6 present more detailed reports, provided by
SEO Analyzer Check, of selected websites social media
presence.
UOL Social Media Signals
Twitter tweets 55.200
Facebook shares 189.600
Facebook likes 156.900
Facebook comments 52.200
Google + pluses 958
LinkedIn shares 1.050
StumbleUpOn views 40
Pinterest pins 2
Total 455.900
Fig. 4. UOL social media signals.
eMAG Social Media Signals
Twitter tweets 11
Facebook shares 8
Facebook likes 0
Facebook comments 0
Google + pluses 1
LinkedIn shares 0
StumbleUpOn views 0
Pinterest pins 0
Total 20
Fig. 5. eMAG social media signals.
WebAIM Social Media Signals
Twitter tweets 410
Facebook shares 114
Facebook likes 27
Facebook comments 28
Google + pluses 19
LinkedIn shares 21
StumbleUpOn views 66
Pinterest pins 128
Total 813
Fig. 6. WebAIM social media signals.
As expected, UOL social networking media presence is
massive in comparison to both others. This is because it is a
news website. WebAIM’s presence is above expected for an
information and service provider website and eMAG is just too
low, being even considered an error for the evaluation tool.
Although social media presence has no relevance on a web
accessibility perspective, it is here stated because of its
importance to SEO.
Finally, an SEO score, which goes from 0 to 100, was
provided by SEO Analyzer Check. The result for each website
is presented in Fig.7.
Fig. 7. SEO score.
UOL website was the higher ranked of the three selected
websites, with 83 points, followed closely by WebAIM
website, with 82 points. The eMAG website, with 69 points,
had the lowest score.
Since UOL website is SEO focused, it was expected that it
would be the higher ranked of the three selected websites.
However, once more, a closer look at the results reveals that
eMAG website, applying only accessibility rules, rank 69
points in the score, just 14 points lower than UOL.
Furthermore, WebAIM website score proved that with the
combination of implementing web accessibility guidelines and
a small effort in SEO-specific techniques is possible to achieve
just as high ranking as a news portal.
UOL lost points in SEO partially because of missing
alternative texts errors, which are totally related with web
accessibility. With some small effort in solving this problem,
the user experience for people with disabilities would be
improved and UOL website would be better ranked in search
engines.
The overall results suggest that there is a strong relationship
between compliance with accessibility guidelines and the
ranking of a website in a search engine.
V. CONCLUSIONS AND FUTURE WORK
The primary objective of this study was to investigate
whether a site developed according to accessibility guidelines
could also be optimized for search engines.
In the first step of this research, the main web accessibility
guidelines were confronted with SEO techniques. After
reviewing 24 selected accessibility guidelines, it was observed
that 22 of them overlap SEO techniques favouring, when
implemented, the positioning of a website in search engines
rankings. None of the 24 selected guidelines contradicted the
SEO techniques.
In the second step of the study, three types of sites were
selected for web accessibility and SEO evaluation, using the
proper tools for each case. Results suggested that a website
applying only accessibility rules can achieve a good
performance on an SEO perspective. In addition, the results
showed that with the combination of implementing web
accessibility guidelines and a small effort in SEO-specific
techniques is possible to a website achieve high ranking in
search engines. At last, results indicated that, with some small
effort, SEO focused websites can solve some web accessibility
problems, improving the user experience for people with
disabilities and getting even better results in search engines
rankings.
In conclusion, the overall results showed that there is a
strong relationship between compliance with accessibility
guidelines and the ranking of a website in a search engine and
that many of the guidelines for both concepts overlap.
One possible direction for this research would be to study
how accessibility rules influence SEO in mobile environment,
by analyzing the differences between a site developed with
responsive design and a mobile-optimized website.
Another way to improve results might require the analysis
of the 23 eMAG 3.1 recommendations that were not
considered in this study to determine whether or not they have
some relevance regarding SEO or if they even contradict SEO
techniques.
At last, another approach for future research would be to
look the other way around, identifying which SEO techniques
can improve web accessibility. This approach could help
finding overlaps other than the ones revealed by this article.
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