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References to Usability and Accessibility Heuristics

The Fluid UX Walkthrough team assessed a number of different heuristics and cognitive walkthrough processes when compiling our own checklist. Below are references and links to these sources, as well as the heuristics themselves. This material is provided as background reading for those who are interested in the published work that informed our own protocol. Many thanks go to Clayton Lewis and Daphne Ogle for their hard work compiling these resources and drafting the UX Inspection Methods and Techniques.

Usability Heuristics

Nielsen and Molich

Here are original Nielsen and Molich heuristics, as refined by Nielsen. In addition, there is a detailed description from Denise Pierotta, Xerox, of specific things to look for when evaluating Nielsen's Heuristics.

Visibility of system status
    The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

Match between system and the real world
    The system should speak the users' language, with words, phrases and concepts familiar to the user, rather than system-oriented terms. Follow real-world conventions, making information appear in a natural and logical order.

User control and freedom
    Users often choose system functions by mistake and will need a clearly marked "emergency exit" to leave the unwanted state without having to go through an extended dialogue. Support undo and redo.

Consistency and standards
    Users should not have to wonder whether different words, situations, or actions mean the same thing. Follow platform conventions.

Error prevention
    Even better than good error messages is a careful design which prevents a problem from occurring in the first place. Either eliminate error-prone conditions or check for them and present users with a confirmation option before they commit to the action.

Recognition rather than recall
    Minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. Instructions for use of the system should be visible or easily retrievable whenever appropriate.

Flexibility and efficiency of use
    Accelerators - unseen by the novice user - may often speed up the interaction for the expert user such that the system can cater to both inexperienced and experienced users. Allow users to tailor frequent actions.

Aesthetic and minimalist design
    Dialogues should not contain information which is irrelevant or rarely needed. Every extra unit of information in a dialogue competes with the relevant units of information and diminishes their relative visibility.

Help users recognize, diagnose, and recover from errors
    Error messages should be expressed in plain language (no codes), precisely indicate the problem, and constructively suggest a solution.

Help and documentation
    Even though it is better if the system can be used without documentation, it may be necessary to provide help and documentation. Any such information should be easy to search, focused on the user's task, list concrete steps to be carried out, and not be too large.

A Heuristic Evaluation Example

An example of a report created through heuristic analysis can be found at WAI Site Analysis Summary

Accessibility Heuristics

WCAG 2.0

Here are the top level WCAG 2.0 Guidelines:

*Principle 1: Content must be perceivable.)

  • Guideline 1.1 Provide text alternatives for all non-text content
  • Guideline 1.2 Provide synchronized alternatives for multimedia
  • Guideline 1.3 Ensure that information and structure can be separated from presentation
  • Guideline 1.4 Make it easy to distinguish foreground information from its background

Principle 2: Interface components in the content must be operable

  • Guideline 2.1 Make all functionality operable via a keyboard interface
  • Guideline 2.2 Allow users to control time limits on their reading or interaction
  • Guideline 2.3 Allow users to avoid content that could cause seizures due to photosensitivity
  • Guideline 2.4 Provide mechanisms to help users find content, orient themselves within it, and navigate through it
  • Guideline 2.5 Help users avoid mistakes and make it easy to correct mistakes that do occur

Principle 3: Content and controls must be understandable

  • Guideline 3.1 Make text content readable and understandable.
  • Guideline 3.2 Make the placement and functionality of content predictable.

Principle 4: Content should be robust enough to work with current and future user agents (including assistive technologies)

  • Guideline 4.1 Support compatibility with current and future user agents (including assistive technologies)
  • Guideline 4.2 Ensure that content is accessible or provide an accessible alternative

Paddison and Englefield

Here are accessibility heuristics from Paddison and Englefield, 2003:

1. Provide meaningful and relevant alternatives to non-text elements

  • Images, graphs, video, sound, image maps, objects (applets, plug-ins, PDF files)
  • If important information is being conveyed, provide a suitable alternative
  • Alternatives provide all users with the same relevant content

2. Support consistent and correctly tagged navigation

  • Always provide a home page link
  • Always provide a skip to main content link
  • Correctly tag headings
  • Meaningfully title frames
  • Correctly tag table headers

3. Allow complete and efficient keyboard usage

  • Allows users to navigate by keyboard alone

4. Respect users' browser settings

  • Permit large font sizes
  • Ensure page layout adjusts itself to suit font size
  • Allow preferred colour settings

5. Ensure appropriate use of standard and proprietary controls

  • Text entry fields, drop-down menus, radio buttons, checkboxes, buttons
  • Ensure controls do not stop the completion of the task

6. Do not rely on colour alone to code and distinguish

  • Verify colour alone is not used for information
  • Ensure contrast is sufficient in images

7. Allow users control of potential distractions

  • Provide a means to stop blinking, flashing, flickering
  •  Allow users to control speed of scrolling e.g. ticker tape

8. Allow users to understand and control time restraints

  • Notify user of time-out
  • Allow users to request more time

9. Make certain the Web site is content compatible with assistive technologies

  • Make certain important and frequent tasks can be completed successfully using assistive technology tools e.g. screen reader, magnifier

Designing Web Content for People with Learning Disabilities

Here are guidelines adapted from http://www.ld-web.org:

Use plain language

  • Clear text:
    • Short Strong Words
    • In Small Groups
    • Make Things Clear
    • Use short sentences and paragraphs; Try to keep separate ideas in separate sentences and paragraphs. Break up long, complex sentences and change them into a few short ones.
    • Use bulleted or numbered lists
    • Break up points into logical steps
    • Use white space to separate ideas
  • Use of illustrations:
    • Illustrate instructions.
    • Illustrate important navigation elements (like contact us, and home).
    • Use well known symbols (like ? for help, < for back).
    • Illustrate important concepts.
    • Avoid distracting animations.
  • Tools to help people find content:
    • A clear site map.
    • Clear and distinct page titles.
    • Topic maps for complex content.
    • Summaries of pages and sections of content.
  • Flexibility:
    • Make text expandable
    • Make pictures expandable
  • To prepare information for use with text readers:
    • Use full stops, semi-colons, commas after headings and bullet points to make the voice pause.
    • Number menu items to aid navigation.
    • Avoid writing full words in capital letters since screen readers may spell them out.
    • Many screen readers may have difficulty with tables. They can mix up the page order.

Cognitive Walkthroughs

Spencer's streamlined cognitive walkthrough

Here are some questions to keep in mind at each step in a task, taken from Spencer's streamlined cognitive walkthrough. Clayton Lewis has added supplementary questions to increase the specific focus on accessibility.

  1. Will the user know what to do at this step?
    • Is complex problem solving needed to figure out what to do?
    • Are the cues provided accessible to the user?
      • Can they be understood by someone who doesn't process text well?
    • Will a user (for example a screen reader user) be able to find the cues?
  2. Will the user be able to carry out the required action?
    • Does carrying out the action require a mouse?
    • Does it require visual monitoring?
    • Does it require fine motor control?
  3. If the user does the right thing, will they know that they did the right thing, and are making progress towards their goal?
    • Is complex problem solving needed to interpret the feedback?
    • Is the feedback accessible to the user?
      • Can it be understood by someone who doesn't process text well?
    • Will a user (for example a screen reader user) be able to find the feedback?

Other Material

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