Artigo Científico

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

[email protected]

Alessandra Sutto Marucci

FCI – Faculty of Computing and Informatics

Mackenzie Presbyterian University

São Paulo, Brazil

[email protected]

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


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


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


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


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


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


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

http://emag.governoeletronico.gov.br/

http://noticias.uol.com.br/

http://webaim.org/

http://webaim.org/

http://webaim.org/intro/

http://webaim.org/blog/

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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