UX is rules. Not Everyone’s Perfect.
Universal Design named the rule in 1997. The industry is still learning it the hard way.
Series Introduction: “Design is rules…” breaks down the named principles and heuristics that UX design actually rests on. Each entry traces one rule set back to the cognitive science behind it.
Somewhere right now, a product team is triaging a lawsuit. WCAG checklist open in one tab, court filing in the other, a designer explaining that accessibility “was on the roadmap.” In 2025 alone, nearly five thousand companies had this exact meeting for the first time. None of them needed a lawsuit to learn the rule. It was written down in 1997.
In this article:
• Why Universal Design’s seven 1997 principles are rules, not values
• Why disability isn’t a statistical edge case, but 16% of the population
• How Microsoft’s Persona Spectrum reveals who a single design decision protects
• Why cheap accessibility “shortcuts” keep failing in court
Written by Krystian M. Frahn, AIinUX framework creator | 4 custom made Anthropic Claude skills in a row used by the author for the research and article creation
The Rule Was Never a Mystery
Universal Design is not a philosophy. It is a checklist, and it has been one since 1997, when the Center for Universal Design formalized seven working principles built to make environments and products usable by everyone, without adaptation. Equitable Use. Flexibility in Use. Simple and Intuitive Use. Perceptible Information. Tolerance for Error. Low Physical Effort. Size and Space for Approach and Use.
That specificity is the point. In my AIinUX practice, I treat vague values as the first thing to distrust — “be inclusive” tells a designer nothing testable, but “Tolerance for Error” tells them exactly what to check. Universal Design distinguishes itself from every looser umbrella term precisely because it names its rules instead of gesturing at a mood.
So when a team discovers, mid-lawsuit, that their product excludes disabled users, they are not encountering a new problem. They are encountering a documented one, with a name, a decade, and seven testable clauses they never opened.
Disability Is Not the Edge Case
Design thinking has a well-worn tool called the extreme user — someone at the outer edge of a product’s behavior curve, useful for surfacing insight precisely because they are unusual. Disability gets filed there constantly. It does not belong there.
Supported with the fact that 16% of a given population might be disabled (WHO), it becomes pragmatic. And remember that disabled people — also those temporarily disabled, that are so hard to take into account — might actually be your desired user group. An extreme user is defined by one product, one task, one edge. Disability is a stable trait carried across every product a person touches.
That distinction is not academic. Confuse the two and a designer starts treating accessibility as optional insight instead of a fixed constraint — which is exactly the mistake the 1997 rule was written to prevent.
The Colors of Disability
Microsoft’s Persona Spectrum, developed by Kat Holmes, does something Universal Design’s seven principles do not: it shows who the rule actually protects. Permanent limb loss, a temporary arm injury, a parent holding an infant with one free hand — the same design constraint, three different people, one spectrum. “Solve for one, extend to many” is the toolkit’s own phrase for it.
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Critics have pushed back, arguing that leaning on temporary and situational framing risks turning permanent disability into a market-sizing exercise instead of centering the people it was for. I take the critique seriously and reject the shortcut it warns against. No excuses and no shortcuts — is for a designer. All of the colors of disability and the count matters for businesses.
Is a spectrum tool corrupted by the moment someone uses it to justify accessibility by its side benefits instead of the mandate itself? Only if the designer lets it be. The tool reveals scale. It does not excuse anyone from the rule.
The Industry Keeps Discovering the Rule the Hard Way
Software engineering has known since Barry Boehm’s 1981 research that fixing a defect costs more the later it is caught — a finding accessibility practitioners now apply directly, noting that early fixes stay low-effort and localized while late remediation means fighting a system already in motion. That is not a cost argument. It is a timing argument, and it should have ended the debate decades ago.
It has not. Plaintiffs filed nearly five thousand web accessibility lawsuits in the United States in 2025 alone, part of a total exceeding twenty-five thousand since 2018. The European Union’s Accessibility Act triggered its first enforcement lawsuits within months of taking effect in 2025. Even the shortcut has been tested and failed: the US Federal Trade Commission fined one automated “accessibility overlay” vendor a million dollars in 2025 for claiming its widget could deliver compliance it never actually produced, a finding over eight hundred accessibility professionals had already been saying in public for years.
Every one of these is a team discovering, expensively, what a seven-point checklist told them for free in 1997.
The lawsuit meeting is still happening somewhere right now. The checklist that would have prevented it has been sitting in a filing cabinet, publicly available, since before most of that team was born. What would change in your next project if you opened it before the roadmap gets written — not after the summons arrives?
Krystian M. Frahn is a UX designer and researcher, supporting Human-Centered Design and exercising the use of AI in the process, creator of AIinUX design framework | linktr.ee/aiinuxdesign
Dictionary
Universal Design
A design philosophy formalized in 1997 into seven named, testable principles, holding that environments and products should be usable by all people without adaptation. It was built to be applied from the first design decision, not retrofitted later.
Persona Spectrum
A Microsoft Inclusive Design tool that maps a single ability limitation across permanent, temporary, and situational cases. It shows how designing for one person with a permanent disability extends real usability benefit to a much larger group.
Extreme User
A design-research concept for someone positioned at the outer edge of a single product’s behavior curve — useful for surfacing unusual insight because they are the exception. Disability does not fit this definition: it is a stable trait carried across every product a person touches, not an edge case tied to one.
Read more:
Story, M. F., Mueller, J. L., & Mace, R. L. (1998). The universal design file: Designing for people of all ages and abilities. Center for Universal Design, North Carolina State University.
Microsoft Design. (2016). Inclusive 101 guidebook. Microsoft. inclusive.microsoft.design/articles/inclusive-101-guidebook
Federal Trade Commission. (2025, January 3). FTC takes action against accessiBe over deceptive claims about AI-powered website accessibility tool. ftc.gov
AIinUXdesign Ally UniversalDesign ISO9241 UXDesign InclusiveDesign
Date: 2026–07–20 | Author: Krystian M. Frahn
AIinUX: linktr.ee/aiinuxdesign
