Accessibility Principles & Best Practices


Understanding Accessibility

Accessibility is not about disability; it’s actually about ability. It’s about making it easy for everyone.
  • Acquire the same information
  • Engage in the same interactions
  • Enjoy the same services

In an equally effective and equally integrated manner, with substantially equivalent ease of use.

Principles for Information and Communication Technology (ICT)

  1. Perceivable: so that individuals with visual impairments can understand the information being conveyed
  2. Operable: navigate to information in multiple methods (not only the mouse)
  3. Understandable: understandable enough so that all different learning styles can engage
  4. Robust: IT products should be compatible with a user’s desired technologies or system preferences


Accessibility ensures everyone can perceive, understand, engage, navigate, and interact with technology regardless of device, software, or product without barriers.

Universal Design Principles

The design is useful and marketable to people with diverse abilities. For example, a website that is designed to be accessible to everyone, including people who are blind and use screen reader technology, employs this principle.
The design accommodates a wide range of individual preferences and abilities. An example is a museum that allows visitors to choose to read or listen to the description of the contents of a display case.
Use of the design is easy to understand, regardless of the user's experience, knowledge, language skills, or current
concentration level. Science lab equipment with clear and intuitive control buttons is an example of an application of this principle.
The design communicates necessary information effectively to the user, regardless of ambient conditions or the
user's sensory abilities. An example of this principle is captioned television programming projected in a noisy sports bar.
The design minimizes hazards and the adverse consequences of accidental or unintended actions. An example of a
product applying this principle is software applications that provide guidance when the user makes an inappropriate selection.
The design can be used efficiently, comfortably, and with a minimum of fatigue. Doors that open automatically for people with a wide variety of physical characteristics demonstrate the application of this principle.
Appropriate size and space is provided for approach, reach, manipulation, and use regardless of the user's body size, posture, or mobility. A flexible work area designed for use by employees who are left- or right-handed and have a variety of other physical characteristics and abilities is an example of applying this principle.

Best Practices for Accessibility

  • Organize content with headings, subheadings, images, videos, and footer are important for usability and accessibility.
  • Use Heading Styles in a logical sequence to give a structure by category or topic.
  • A written description of images and/or objects that can be read by a blind or low vision using screen reader technology.
  • Screen readers and other assuasive technologies can’t convert images into words/texts. Thus providing captions are universal and accessible for everyone. 
  • Recommend brief descriptive text within 8 to 80 characters long.
  • Provide descriptions if using color to convey meaning
  • Download Colour Contrast Analyzer onto your computer (PC/Mac) to ensure accessible contrast or use an online contrast checker from WebAIM.
  • WCAG Level AA requires a contrast ratio of at least 4.5:1 for normal sized text (12 pt. font) and 3:1 for large text (14 pt. font).
  • Coblis Color Blindness Simulator

Users should be able to get to content without using a mouse
• Keyboard
• Hearing
• Touch

Users should be able to access content on different screens (phone, tablet, etc.)

• "Read more", "click here", "email me", or "continue" are vague and redundant.

Link text should clearly identify the target of each link. Good link text should not be overly general.
• Make sense when read out of context.
• Describe the destination (document name, website).
• Be unique for unique destinations.

Do not use color links as the only method to convey important information.

• Tab order should read from the upper left to the lower right, and make sense to both sighted and visually impaired users.


How to Evaluate Accessibility Based on Four Principles

  1. Font: Is the font styling easy to read?
  2. Color: Is the font color easy to read?
  3. Tab: Can a user "tab" through the functions?
  4. Enlarge: Can a user make the font bigger? (ctrl +)