What is the Difference between Accessible, Universal and Usable Design?

This is a question we sometimes hear when working with designers, architects and engineers. While each term has different criteria, focus and enforceability, the overall goals are quite similar: to create spaces, objects, facilities and experiences that include the most people possible.

In a recent article published by DO-IT (Disabilities, Opportunities, Internetworking, and Technology) at the University of Washington, they succinctly outline the variances in terminology:

Accessible Design

Accessible design is a design process in which the needs of people with disabilities are specifically considered. Accessibility sometimes refers to the characteristic that products, services, and facilities can be independently used by people with a variety of disabilities. Accessibility as a design concern has a long history, but public awareness about accessibility increased with the passage of legislation such as the Americans with Disabilities Act (ADA), which mandated that public facilities and services be fully accessible to people with disabilities.

In 1998 an amendment to Section 508 of the Rehabilitation Act of 1973 was passed. The amendment mandated that the Access Board develop accessibility standards for software, hardware, websites, videos, and other information technology. Although these standards apply directly to the development, procurement, modification, and use of information technology of U.S. federal agencies, many states, educational institutions, and other entities have adopted them as one way to meet their ADA obligations. The Web Accessibility Initiative of the World Wide Web Consortium has also developed guidelines and comprehensive resources for designing accessible web pages.

Universal Design

Universal design is a broader concept that is defined by The Center for Universal Design at North Carolina State University as "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."

Sidewalks with curb cuts and doors that automatically open when a person moves near them are examples of universally designed products. They benefit people with disabilities, parents with baby strollers, delivery workers, and others. Human characteristics considered in universal designs may include age, gender, stature, race/ethnicity, culture, native language and learning preference.

In the case of information technology, products that are universally designed are accessible to and usable by people with a wide variety of characteristics, including different types of disabilities. These products are often designed to eliminate or minimize the need for assistive technologies. At the same time, they are compatible with common assistive hardware and software devices. For more information about applications of universal design, consult DO-IT's Applications of Universal Design.

Both accessible and universal design are concerned with addressing the needs of users beyond those considered to be "average" or "typical."

Usable Design

Like accessible and universal design, usable design serves to create products that are easy and efficient to use. Usability has been defined by the International Organization for Standardization as the "effectiveness, efficiency, and satisfaction with which a specified set of users can achieve a specified set of tasks in a particular environment." Usability engineers test the ease at which users can learn to operate a product and remember how to do so when they return to the product at a later time.

Unfortunately, people with disabilities are not always included in usability tests. Therefore, many products that perform well in usability tests are not accessible to people with disabilities. Increasingly, accessible and universal design considerations are being addressed by usability professionals. For example, accessibility is now a topic on high-profile usability websites such as Usability.gov and Usability First.

Usability shares some key goals with accessibility and universal design. Designers in all three disciplines seek to create product features that are easily discovered and operated by the user. Usability engineers are concerned with aspects of the user experience, that include:

• Learnability: Can users easily learn how to operate the product, and can they remember how to perform tasks when they return to the product the next time?
• Consistency: Are product features clearly and consistently labeled?
• Efficiency and effectiveness: Can users perform tasks with a minimal amount of effort and achieve their goals successfully?

Click here for the entire DO-IT article | Click here for technical criteria for Accessible Design (2010 ADA Standards) 

Click here for more info about Universal Design in Corada