Understanding the Principles of Accessibility Testing

Shahid Algur, Quality Assurance Architect


The significance of digital accessibility in the present era cannot be underestimated. Failing to ensure a genuinely accessible website exposes companies to potential legal and financial consequences of a serious nature.
Accessibility is the act of ensuring that information, activities, and/or environments are comprehensible, meaningful, and accessible to a broader range of users.

Applications are created and built to make them accessible to individuals with disabilities. These individuals should be able to use, perceive, navigate, and engage with or contribute to the web. It is the practice that ensures that all users can use the application, irrespective of age, disability, or on any devices with different Hardware/Software.

The development of Web Content Accessibility Guidelines (WCAG) is a collaborative effort between the W3C process and various individuals and organizations worldwide. The primary objective is to establish a universally accepted standard for web content accessibility that caters to the requirements of individuals, organizations, and governments on a global scale.

Need of Accessibility

Statistics as per WHO (World Health Organization)

  • 15% of the world's population, or around 1.3 billion people, have significant disability.
  • 2.2 billion people have vision impairments.
  • Over 430 million people worldwide have disabling hearing loss.
  • More than 200 million people have intellectual disabilities.

It can be broadly classified into the following categories:

  • People with vision impairment
  • Auditory disabled persons.
  • Intellectual/Cognitive disabled people.
  • Speech-impaired persons
  • Physically/Motor/Locomotor disabled persons.
  • Seizure and vestibular disabled people.
  • Using devices with different configurations.
  • Elders

Impact on products without Accessibility

Digital accessibility possesses a distinct moral dimension, as businesses bear an ethical responsibility towards their customers and society at large to foster inclusivity for all individuals.
Failure to ensure the accessibility of digital products signifies a failure to fulfil this obligation by organizations.

  1. Lack of Accessibility principles may reduce traffic and reach limited users: The best practices of search engine optimization (SEO) overlap with the best practices of digital accessibility. If your site isn’t accessible, you may receive less traffic from search engines.
    Accessibility can also benefit your social media marketing strategy, increasing engagement across Facebook, Twitter, and other platforms.
  2. Creates frustration and exclusion in disabled users.
  3. Legal challenges and penalties.
  4. Negative user experiences for all users.
  5. Risk of lawsuits.

Web Standard for Accessibility (WCAG)

The WCAG is an internationally recognized set of guidelines for digital accessibility. Web Content Accessibility Guidelines (WCAG) define how to make Web content more accessible to people with disabilities.
It was established and is managed by the international web standards group, the W3C. WCAG comes in 3 levels: A, AA, and AAA.

WCAG Principles:


Users must be able to perceive and comprehend the information and user interface components presented to them. It is crucial that the information is not invisible to any of their senses, ensuring a seamless user experience.

  • The text is readable, and the page is uncluttered.
  • Appropriate text alternatives are provided for media content, such as alt text for images, or accurate transcripts, captions, and audio description for audio /video files.
  • To make information conveyed by prerecorded audio and video content available to all users.
  • Info & Relationship – Everything should be organized logically, and sequence should be maintained.
  • User of appropriate colours, and contrast ratio.


The operability of user interface components and navigation is crucial, as it should not demand any interaction beyond the user's capabilities.

  • The site is easily navigable and can be accessed using a range of assistive technologies, such as screen readers, screen magnifiers, and text-to-speech software.
  • Keyboard-only functionality is ensured.
  • Page elements do not disappear abruptly, giving older users, for instance, enough time to interact with them.
  • Elements also do not move around rapidly or blink; doing so can cause issues for users with ADD or photosensitive epilepsy, respectively.
  • Websites or apps should not flash or blink three times in one second or the flash should be below the general flash and red flash thresholds.
  • Bypass blocks, sometimes referred to as skip links, are hidden links that keyboard navigators use to skip past repeat or lengthy sections of content.
  • Link purpose to help users to understand the purpose of each link.


Users should be able to comprehend both the information and the functioning of the user interface for it to be considered understandable.

  • Text is written in simple language and is easily translatable. Users are notified about any errors they have made when filling out a form.
  • Menus & buttons should be consistent.
  • Consistent Navigation
  • To make sure users know when something goes wrong and can figure out what's the problem.
  • Ensure that user agents, including assistive technologies, can accurately interpret and parse content.


The content should possess sufficient robustness to ensure reliable interpretation by a diverse range of user agents, encompassing assistive technologies.

  • Site content is compatible with existing and future technologies.
  • Ensure that all tools used by users, including those that assist with disabilities, can understand, and organize the information correctly.

WCAG Compliance Levels:

There are also three levels of conformance. The higher the level, the more constraining it is on design:

Level A

This is the minimum suggested accessibility standard of compliance in WCAG. If the application fails to comply with this standard, it may have severe accessibility concerns.

This can be achieved by complying following guidelines:

  • Character key shortcuts to give users the ability to turn off keyboard shortcuts.
  • Pointer gestures that avoid complex point gestures such as two-finger pinch/zoom.
  • Pointer cancellation that avoids accidentally triggering touch or mouse events.
  • Label in name, where labels contain visual text.
  • Motion actuation, where functionality that uses device or user motion is available in the user interface to enable the disabled.

Level AA

This is the most desirable level of guidelines having good readable text along with good contrast ratio and support for interface zoom. Applications complying with this level are reasonably accessible for most users.

This can be achieved by complying following guidelines:

  • Reflow to prevent scrolling.
  • Functionality and content available in both portrait and landscape.
  • Non-text contrast with images having a contrast ratio of at least 3:1 against adjacent colours.
  • Text spacing that lets users override spacing and line height.
  • Content on hover or focus, where new content appears only on focus or mouseover. • Status messages that indicate errors.

Level AAA

This is the highest level of accessibility standards. WCAG guidelines AAA is considered to be ideal. To achieve Level AAA conformity, content must adhere to every WCAG recommendation (including Level AA and Level A success criteria).

They must adhere following guidelines:

  • Identify the purpose, where the purpose of content is programmatically determined.
  • Include timeouts that warn users of inactivity and subsequent data loss.
  • Allow animations from interactions to be disabled unless it is essential to functionality.
  • Target size, with pointer inputs at least 44 by 44 CSS pixels.
  • Include concurrent input mechanisms where web content does not restrict use of input modalities.

Accessibility Testing

Accessibility Testing:

It is a technique to verify that the digital content (Web, Mobile apps, Desktop Apps) is usable to all users, including those with disabilities like vision impairments, deafness, and other cognitive conditions, etc. 

Factors to be considered while performing Accessibility tests:

  • The main goal of Accessibility testing is to ensure that there should not be any barriers to using the application. All users with varied disabilities and other factors should be able to easily use the application. Accessibility testing is a subset of usability that ensures ease of use and users under consideration are people with some disabilities.
  • SIt needs to ensure that the application is compatible with assistive technologies such as –
  • Screen Magnifier – It helps users to magnify the size of images, graphics, and text. .
  • Screen Reader – Screen Reader provides assistive technology to people suffering from visual impairment by reading the text displayed on the screen with the speech synthesizer or braille display.
  • Speech Input Software- Provides people with an alternate way to type text and control the computer.
  • Alternative input devices- Some users may not be able to use a mouse or a keyboard to use computers.
  • Meeting the requirements of individuals with diverse disabilities
  • Identify and understand the distinct needs associated with each disability and subsequently align them with the most effective techniques available.
  • Use optimal techniques and methodologies that cover all disabilities and dimensions.
  • Ensure that web accessibility standards are followed.
  • Design Considerations – Some important factors that comply with design standards –
  • Colour Contrast –Using proper contrast between different elements of a page is important for both low-sighted and colour-blind users.
  • Hierarchy and Layout –The design pattern of the application should be logical and organized. It should remain the same and consistent throughout.
  • Typography –The font should be clear and readable.
  • Text Spacing
  • Hyperlinks –Hyperlinks should stand out from text and should be easily recognizable.
  • Style Focus –To help keyboard-only users convey where they are on a page in the absence of a mouse cursor. It displays a focus ring around the currently focused element.
  • Text – It provides a description of the image. As screen readers are unable to interpret images, this feature enables individuals with visual impairments to associate the image with its corresponding text.

How to perform Accessibility Tests?

Accessibility testing ensures that the application is accessible to all users, and it relies on the WCAG principles as the foundation for conducting these tests. The complexity of tests aligns with the domain and nature of the application.


  • Code Review – The process of Code Review involves the validation of an application against established standards. This is achieved through thoroughly inspecting the HTML, CSS, and JavaScript components to ensure that they conform to the Web Content Accessibility Guidelines (WCAG).
  • Accessibility Scanners - The Accessibility Scanner is a tool that scans the screen and offers recommendations to enhance the accessibility of your application. These suggestions are based on various factors, including content labels, touch target size, and clickable items.
  • User Experience Review– TA comprehensive UX review entails the examination of significant design elements within an application to assess its usability and accessibility. The elements scrutinized during the UX review are –
      • Visual structure
      • Logical arrangement of components
      • Review of the context of user journey & navigation
      • Menus
      • Size of buttons, and labels
      • Pop-ups
      • Links/Hyperlinks
      • Scrolling
      • Zoom IN / Zoom OUT
  • Manual Accessibility Tests using Screen Readers - Screen Readers facilitate the conversion of digital text into an audio format, enabling users to engage with web applications in a non-visual manner. This functionality proves particularly valuable for individuals with visual impairments, as it audibly articulates the web content displayed on the screen, allowing them to navigate digital material without relying on visual cues.
  • There are various accessibility principles that can be addressed using a range of manual and automated tools.


Author: Shahid Algur. Posted on Jan 30, 2024
 More Articles