Module 1: Terminology

1 Terminology

There are three concepts that we'll refer to as we build our understanding of  how accessibility affects the design and delivery of educational materials. They are accessibility, usability, and universal design.

Accessibility

Accessibility is a measure of how easy or difficult it is for a diverse population of users to gain access to a product, service, or environment. The term is most often used with reference to users with some form of disability; access may be direct (unassisted) or indirect (via some sort of assistive device or technology).

The Web Content Accessibility Guidelines Links to an external site. (WCAG) developed by the World Wide Web Consortium Links to an external site. (W3C) are a globally recognized standard, and they evaluate the accessibility of materials using four criteria.

Is it perceivable?  Is the material available to the senses?

Is it operable? Can the user interact with all controls and interactive elements?

Is it understandable? Is the content clear and unambiguous?

Is it robust? Can a wide range of technologies access it?

Usability

Usability refers to how well the tool or material does what the user wants it to do. 

How effective is it--does it accomplish the intended goals?

How efficient is it--does it do what's needed with a reasonable amount of time and effort?

How satisfied are users with its performance?

These factors are influenced by who the users are, what they want to accomplish, and the context in which they're trying to do it.

Universal Design

Universal design is the intersection of accessibility and usability.

The Principles of Universal Design The design of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialized design. 1. Equitable Use: The design is useful and marketable to people with diverse abilities. 2. Flexibility in Use: The design accommodates a wide range of individual preferences and abilities 3. Simple and Intuitive Use: Use of the design is easy to understand, regardless of the user’s experience knowledge, language skills, or education level. 4. Perceptible Information: The design communicates necessary information effectively to the user, regardless of ambient conditions or the user’s sensory abilities. 5. Tolerance for Error: The design minimizes hazards and the adverse consequences of accidental or unintended actions. 6. Low Physical Effort: The design can be used efficiently and comfortable and with a minimum of fatigue. 7. Size and Space for Approach and Use: Appropriate size and space is provided for approach, reach, manipulation, and use regardless of user’s body size, posture, or mobility.

When we apply the principles of universal design to materials we create, we ensure that we're presenting them in such a way that they are of the most use to the greatest possible number of people. For example, adding captions to a video not only makes it accessible to deaf and hard-of-hearing viewers, it provides a resource for nonnative speakers, or users of a different dialect. It can also help develop literacy skills, and it makes video content more electronically  searchable. 

Since different populations have different needs, designing with a universal perspective in mind  will often mean offering multiple versions of the same material. For instance, a bar graph or pie chart may help a person with certain cognitive disabilities to visualize data, but a blind user will be better able to interpret the same data in tabular format.

Sources

What is usability? Links to an external site. http://www.usabilitynet.org/management/b_what.htm

Accessibility Links to an external site. https://en.wikipedia.org/wiki/Accessibility