By Sarah Horton and David Sloan — Some accessibility principles emerged from efforts to create accessible and inclusive physical environments and products. The Principles of Universal Design were developed in 1997 by a multidisciplinary team at North Carolina State University and remain a useful resource for digital product engineers. Universal design (UD) is defined 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.” The seven principles of UD summarize the core characteristics of an accessible product or environment, and each has supporting guidelines.
- Equitable Use: The design is useful and marketable to people with diverse abilities.
- Flexibility in Use: The design accommodates a wide range of individual preferences and abilities.
- Simple and Intuitive Use: Use of the design is easy to understand, regardless of the user’s experience, knowledge, language skills, or current concentration level.
- Perceptible Information: The design communicates necessary information effectively to the user, regardless of ambient conditions or the user’s sensory abilities.
- Tolerance for Error: The design minimizes hazards and the adverse consequences of accidental or unintended actions.
- Low Physical Effort: The design can be used efficiently, and comfortably, and with a minimum of fatigue.
- 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.
The Principles of Universal Design are known and used throughout the world, sometimes with modifications to fit the context of use and the culture and practices of the location. They can be applied to a range of contexts, including the physical environment, education, and technology, to address diverse user accessibility needs. For example, one offshoot is Universal Design for Learning, or UDL, which applies UD principles to teaching and learning.
As an engineer focusing on digital accessibility, these principles provide a framework for implementing accessibility core attributes. For example, the attributes of compatibility and adaptability are based on Principle 2, Flexibility in Use. Digital products that work with a user’s assistive technology and adapt to different contexts of use support flexibility in use because the product accommodates different use cases. And because those attributes are native to the product, they also support Principle 1, Equitable Use, since all users can enjoy the benefits of the same product.
Familiarity with the intent of each UD principle can help you avoid getting bogged down in the more technical details of accessibility. UD guides thinking and decision‑making toward using integrated, design‑focused solutions rather than technical workarounds to address user accessibility needs and advance digital inclusion.
From Horton, S., & Sloan, D. (2024). What Every Engineer Should Know About Digital Accessibility. CRC Press, Boca Raton, Florida.
Principles of Universal Design (1997). Compiled by advocates of Universal Design in 1997. Participants are listed in alphabetical order: Bettye Rose Connell, Mike Jones, Ron Mace, Jim Mueller, Abir Mullick, Elaine Ostrof, Jon Sanford, Ed Steinfeld, Molly Story, Gregg Vanderheiden. The Principles are copyrighted to the Center for Universal Design, School of Design, State University of North Carolina at Raleigh, USA.
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