The Tyrer Framework

The Tyrer Framework is a theory of accessibility by Charli-Jo Tyrer, published by Carrados in 2026. Its central claim is that accessibility is not accommodation; it is information integrity. It draws on about four decades of lived experience as a blind user of access and assistive technology, and on the observation that today's problems are not new failures but the same failure recurring under new names.

It has four parts and a synthesis: a law that diagnoses, a scale that maps, a doctrine that prescribes, and an account of why artificial intelligence breaks the pattern.

Tyrer's Law

See Tyrer's Law.

In open technological systems, inaccessibility tends to increase over time as interfaces drift toward the dominant sensory modality of their designers.

The law describes system behaviour, not intent. Most designers are sighted, and for them visualisation is a thinking tool, so as a system grows its instinctive response is visual: dashboards instead of logs, icons instead of labels, layout instead of sequence. "This is not carelessness. It is cognition." Each cycle adds visual complexity, and accessibility, always reactive, trails behind. The result is a ratchet.

What the drift produces is not inconvenience but information casualties: events in which relevant information fails to reach an observer in time to inform perception, action or participation. The pattern persists because the people it harms are the least represented in design, so sighted teams don't notice the regression until it is entrenched. Standards such as WCAG are the most disciplined counter-force there is, and permanently necessary, but "they slow the law; they do not repeal it."

The Tyrer Accessibility Scale

See Tyrer Accessibility Scale.

Modelled on the Kardashev Scale, which ranks civilisations by the energy they harness, the Tyrer Scale ranks them by how much environmental information reaches every observer, whatever their senses. The two are independent: a civilisation could harness its star and still fail to tell a blind citizen it is safe to cross the street.

• Type 0, Visual Dominance: information is visual first, and accessibility is retrofitted translation. Full WCAG compliance is the best this paradigm can do: "The floor holds, but the ceiling is fixed." Human civilisation in the early twenty-first century is Type 0.
• Type I, Structured Information: visual, spoken and agent interfaces are all generated from the same underlying data, as native siblings rather than translations. Achievable with current technology.
• Type II, Environmental Metadata: the physical world itself broadcasts machine-readable descriptions of its geometry, state and purpose. Mute objects cease to exist.
• Type III, Perceptual Sovereignty: no observer's access to reality depends on which senses they happen to have. The probability of an information casualty approaches zero: the Zero Information Casualty condition.

Types 0 and I are engineering claims about the present; Types II and III are the philosophical direction. "The near end is a measurement; the far end is a direction."

Classical and generative accessibility

Classical accessibility makes fixed artefacts accessible: semantic markup, alt text, keyboard handlers, standards. It is the deterministic floor, and its necessity is permanent. But interfaces are increasingly generated at the moment of use, so the fixed artefact no longer exists by the time the user arrives. The framework calls this the move from a Newtonian web to a quantum one, and the practice that follows it generative accessibility: an interface in superposition until an observer arrives, collapsing into a rendering for a sighted user, another for a blind user and a third for an AI agent, none of them the original.

It also names a convergence: AI agents and assistive technology now need the same things from systems: explicit intent, deterministic state, clear hierarchy and no visual noise. For the first time, the mainstream industry's incentives line up with accessible design.

The transition has three dangers: fragmentation, as users inhabit different versions of the same system; silent failure, as a system quietly simplifies what a user is shown; and the verification burden of checking whether a generated summary reflects the data or the system's guess. The answer is governance, not compliance, beginning with the Right to Inspect: no user should have to accept a generated interpretation they cannot interrogate. "The sidecar becomes the chassis."

The Tyrer Doctrine

See Tyrer Doctrine.

Systems should be engineered so that no critical environmental information is accessible through only a single sensory channel.

Its three principles:

1. Accessibility is information integrity, not accommodation. A single sensory channel is a single point of failure.
2. Missing signals are system failures, not user limitations.
3. The deterministic floor is permanent; the generative ceiling is the frontier.

The AI structural break

See AI structural break.

No earlier technology disrupted Tyrer's Law; assistive technology mitigated it and standards slowed it. AI is the first widely deployed technology that can move from information to perception without encoding it visually first: from interface-first to intent-first. Say what you want, and the result arrives in whatever form you can receive.

The break is real, but its direction isn't guaranteed. On one path AI becomes the most powerful engine of visual drift yet; on the other it becomes a cognitive intermediary, and the law weakens. Only the second path leads to Type I, and "the choice between them is not technical; it is political, economic, and ethical."

Why it matters

If the framework is right, accessibility engineering is core maintenance of information infrastructure, not a specialism; progress along the scale is a real measure of a civilisation; the present is a window that can be used or wasted; and information casualties are system failures with measurable costs. "The endpoint is not utopian. It is an engineering target: zero information casualties."

Behind the scenes

The Tyrer Framework is real. It is published in full, under CC BY-SA 4.0, as a paper on Carrados, with a plain-language rendering, Why accessibility keeps getting worse. Its endpoint gives its name to the Zero Information Casualty design standard, to which charli.info, carrados.com and blind-ant.com are built. This entry summarises the paper; the paper is the authority.