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Universal Design Performance Measures for Products

Resources on Accessible Design Principles and Performance Measures

There are many resources that address accessible design, including a number on the Web:

A good reference from the engineering academic community is Erlandson RF and Babbitt BC (2001), "The Movement of Accessible Design Principles into Mainstream Engineering: Now and Then," in Emerging & Accessible Telecommunications, Information & Healthcare Technologies, Winters JM, Robinson C, Simpson R & Vanderheiden G., eds, pp. 2-18, RESNA Press, Arlington.

Designers should be especially cognizant of the Principles of Universal Design (available as pdf), as developed through the Center for Universal Design by a working group in 1997 (Story, 1998; Story and Mueller, 2002):

  1. Equitable Use
  2. Flexibility in Use
  3. Simple and Intuitive Use
  4. Perceptible Information
  5. Tolerance for Error
  6. Low Physical Effort
  7. Size and Space for Approach and Use

These principles were developed for both the built environment and product design. Since our focus is on product design, it is instructive to add, next to each principle, more pragmatic performance measures. The following table includes both the original consensus guidelines from the working group (left column) and field-tested usable product design concepts, for your consideration. Of note is that many of these cannot always be fully achieved, and there are not statements that can be answered with a "yes" or "no" but rather there is often a continuum. But they are worth striving for.

 

Universal Design: Principles & Performance Measures

[adapted from Story and Mueller (2002), Universal Design Performance Measures for Products: A Tool for Assessing Universal Usability, in Emerging and Accessible Telecommunications, Information and Healthcare Technologies (Winters et al, eds.), pp. 19-28, RESNA Press, Arlington.]

Performance Measures for Products

Principle One - Equitable Use: The design is useful and marketable to people with diverse abilities
Provide the same means of use for all users; identical whenever possible; equivalent when not. All potential users could use this product in essentially the same way, regardless of differences in personal capabilities.
Avoid segregating or stigmatizing any users. Potential uses could use this product without feeling segregated or stigmatized because of differences in personal capabilities.
Make provisions for privacy, security, and safety equally available to all users. Potential users of this product have access to all features of privacy, security, and safety, regardless of personal capabilities.
Make the design appealing to all users. This product appeals to all potential users.
Principle Two - Flexibility in Use: The design accommodates a wide range of individual preferences and abilities
Provide choice in methods of use. Every potential user can find at least one way to use this product effectively.
Accommodate right- or left-handed access and use. This product can be used with either the right or left had alone.
Facilitate the user's accuracy and precision. This product facilitates (or does not require) user accuracy and precision.
Provide adaptability to the user's pace. This product can be used at whatever pace (quickly or slowly) the user prefers.
Principle Three - Simple and Intuitive Use: The design is easy to understand, regardless of the user's experience, knowledge, language skills, or current concentration level
Eliminate unnecessary complexity. This product is as simple and straightforward as it can be.
Be consistent with user expectations and intuition. An untrained person could use this product without instructions.
Accommodate a wide range of literacy and language skills. Any potential user can understand the language used in this product.
Arrange information consistent with its importance. The most important features of this product are the most obvious.
Provide effective prompting and feedback during and after task completion. This product provides feedback to the user.
Principle Four - Perceptible Information: The design communicates necessary information effectively to the user, regardless of ambient conditions or the user's sensory abilities.
Use different modes (pictorial, verbal, tactile) for redundant presentation of essential information. This product can be used without hearing.
Maximize "legibility" of essential information. This product can be used without sight.
Differentiate elements in ways that can be described (i.e., make it easy to give instructions or directions). The features of this product can be clearly described in words (e.g., in instruction manuals or on telephone help lines).
Provide compatibility with a variety of tech niques or devices used by people with sensory limitations. This product can be used by persons who use assistive devices (e.g., eyeglasses, hearing aids, sign language, or service animals).
Principle Five - Tolerance for Error: The design minimizes hazards and the adverse consequences of accidental or unintended actions.
Arrange elements to minimize hazards and errors: most used elements, most accessible; hazardous elements eliminated, isolated, or shielded. Product features are arranged according to their importance.
Provide warnings of hazards and errors. This product draws the user's attention to errors or hazards.
Provide fail safe features. If the use makes a mistake with this product, it won't cause damage or injure the user.
Discourage unconscious action in tasks that require vigilance. This product prompts the user to pay attention during critical tasks.
Principle Six - Low Physical Effort: The design can be used efficiently and comfortably and with a minimum of fatigue.
Allow user to maintain a neutral body position. This product can be used comfortably (e.g., without awkward movements or postures).
Use reasonable operating forces. This product can be used by someone who is weak or tired.
Minimize repetitive actions. This product can be used without repeating any motion enough to cause fatigue or pain.
Minimize sustained physical effort. This product can be used without having to rest afterward.
Principle Seven - Size and Space for Approach & Use: Appropriate size and space is provided for approach, reach, manipulation, and use regardless of user's body size, posture, or mobility.
Provide a clear line of sight to important elements for any seated or standing user. It is easy for a person of any size to see all the important elements of this product from any position (e.g., standing or seated).
Make reach to all components comfortable for any seated or standing user. It is easy for a person of any size to reach all the important elements of this product from any position (e.g., standing or seated).
Accommodate variations in hand and grip size. This product can be used by a person with hands of any size.
Provide adequate space for the use of assistive devices or personal assistance. There is enough space to use this product with devices or assistance (e.g., wheelchair, oxygen tank, or service animal).