Universal design principles 1–3

6 min read · BoK 2E· p. 42–42

Learning objectives (3)

Name the seven universal design principles in order
Explain principles 1 (Equitable Use), 2 (Flexibility in Use), and 3 (Simple and Intuitive Use)
Apply principles 1–3 to physical and digital design scenarios

Why it matters

The seven principles of universal design, developed by Ron Mace and colleagues at North Carolina State University, provide a framework for evaluating and guiding design decisions across physical environments, products, and digital systems. The CPACC exam tests both the names of all seven principles and the ability to apply them to scenarios. This lesson covers principles 1–3. (BoK p. 42)

The seven principles: overview

The seven principles of universal design are:

Equitable Use
Flexibility in Use
Simple and Intuitive Use
Perceptible Information
Tolerance for Error
Low Physical Effort
Size and Space for Approach and Use

Each principle has a definition and a set of guidelines. The principles apply to both physical and digital design, though their application looks different in each context.

Principle 1: Equitable use

The design is useful and marketable to people with diverse abilities. It provides the same means of use for all users — identical where possible, equivalent where not. It avoids segregating or stigmatizing any users. (BoK p. 42)

Key guidelines under Principle 1:

Provide the same means of use for all users; avoid separate but equivalent solutions where possible.
Design the main experience to be usable by all — not a special accessible entrance or a separate accessible version.
Make the design appealing to all users.

Digital example: A website that provides the same content to all users, formatted to work with screen readers, does not hide content behind an “accessibility mode” toggle or provide a separate simplified “accessible version.” Accessible versions are a stigmatizing workaround; Principle 1 calls for equitable access through the main design.

Physical example: An automatic door that opens for everyone — not a door with a button accessible only to wheelchair users, positioned behind the main flow of foot traffic.

Principle 2: Flexibility in use

The design accommodates a wide range of individual preferences and abilities. It provides choice in methods of use, supports left- and right-hand access, facilitates accuracy and precision, and provides adaptability to the user’s pace. (BoK p. 42)

Key guidelines under Principle 2:

Provide choice in methods of use.
Accommodate right- or left-handed access and use.
Facilitate the user’s accuracy and precision.
Provide adaptability to the user’s pace.

Digital example: A form that can be completed using a mouse, keyboard, touch, or voice input — without any function limited to a single input method — satisfies Principle 2. An interface that requires drag-and-drop without offering a keyboard alternative does not.

Physical example: Scissors designed for both right- and left-handed users. A tool with interchangeable grips for single-handed or two-handed use.

Principle 3: Simple and intuitive use

The design is easy to understand regardless of the user’s experience, knowledge, language skills, or concentration level. It eliminates unnecessary complexity, is consistent with user expectations, accommodates a wide range of literacy and language skills, and provides effective prompting and feedback. (BoK p. 42)

Key guidelines under Principle 3:

Eliminate unnecessary complexity.
Be consistent with user expectations and intuition.
Accommodate a wide range of literacy and language skills.
Arrange information consistent with its importance.
Provide effective prompting during and after task completion.

Digital example: A form with clear labels, logical sequence, inline validation, and a progress indicator for multi-step processes applies Principle 3. A form with unlabeled fields, non-obvious error recovery, and no indication of progress does not.

Physical example: A thermostat with a large, clearly labeled dial that increases temperature when turned clockwise and decreases it when turned counterclockwise — consistent with the mental model most users hold.

Real-world example

A university student center was renovated. The original design included a separate “accessible entrance” in the rear of the building that required disabled students to navigate through a service corridor. A UD redesign eliminated the separate entrance and made the main entrance fully accessible — automatic doors, level threshold, clear path to all spaces. This directly applies Principle 1 (equitable, non-stigmatizing access) and removes a design that provided an equivalent but inferior experience.

Key terms

Equitable use: UD Principle 1: the design is useful and marketable to people with diverse abilities, providing the same or an equivalent experience for all users. (BoK p. 42)
Flexibility in use: UD Principle 2: the design accommodates a wide range of individual preferences and abilities, offering choices in method of use. (BoK p. 42)
Simple and intuitive use: UD Principle 3: the design is easy to understand regardless of the user's experience, knowledge, language skills, or concentration level. (BoK p. 42)
Stigmatizing design: A design feature that marks users with disabilities as different or inferior by providing them a separate, inferior, or conspicuous experience. (BoK p. 42)

Check yourself

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Which universal design principle states that the design should provide the same means of use for all users — identical where possible, equivalent where not — and should avoid segregating or stigmatizing any users?

a) Principle 2: Flexibility in Use
b) Principle 3: Simple and Intuitive Use
c) Principle 1: Equitable Use — correct answer
d) Principle 4: Perceptible Information

Explanation: Universal design Principle 1 (Equitable Use) requires that the design be useful to people with diverse abilities by providing the same means of use for all — identical where possible, equivalent where not — and that the design avoid segregating or stigmatizing any users.

A kitchen tool manufacturer designs a vegetable peeler that can be used with equal ease by left-handed and right-handed users. Which universal design principle does this design primarily exemplify?

a) Principle 1: Equitable Use — the same tool serves all users without a separate version
b) Principle 2: Flexibility in Use — the design accommodates both left- and right-handed users — correct answer
c) Principle 6: Low Physical Effort — the design reduces the force needed to peel vegetables
d) Principle 7: Size and Space — the design fits different hand sizes

Explanation: Universal design Principle 2 (Flexibility in Use) explicitly calls for accommodating right- and left-handed access and use. A peeler equally usable by both left- and right-handed users directly applies this guideline.

A university maintains a standard website and a separate 'accessible version' with simplified layout and reduced features for users with disabilities. An accessibility consultant argues this approach fails universal design principles. What is the primary UD critique of this approach?

a) The accessible version is likely to fall behind the main site in features and updates, creating a maintenance problem
b) The separate version violates Principle 1 (Equitable Use) by segregating users with disabilities and providing them a different, potentially inferior experience — correct answer
c) The separate version violates Principle 3 (Simple and Intuitive Use) because having two sites creates confusion about which version to use
d) The separate version is acceptable under universal design as long as both versions have equal features and are equally maintained

Explanation: Universal design Principle 1 (Equitable Use) requires that the design provide the same or equivalent means of use without segregating or stigmatizing users. A separate 'accessible version' explicitly segments users, typically provides fewer features, and communicates that disabled users are not the primary audience — all contrary to the equitable use principle.

Sources

BoK references

Section 2E — IAAP CPACC Body of Knowledge v4.0 (Oct 2023), p. 42