Methodology & trust

Current methodology version: v0.4.3. Every published score records the version that calculated it, and the rules only change through a documented review, never silently.

What the score measures

A SARScore describes one access route: the real journey from a practical arrival point to a specific destination, including the approach, the entrance, vertical movement and the internal journey. If the practical starting point, entrance or destination differ materially, they are different access routes. It is scored in four stages: approach (arrival point to the entrance), entry (gaining access through it), vertical movement (reaching the destination's level) and the internal journey (entrance to the final destination). Routes that end at the entrance, such as a house front door, mark the interior stages as not applicable rather than pretending to know them.

Contributors record observable facts: distance bands, surfaces, steps and whether they were avoidable, entry mechanisms, observed waits, lift status, corridors and doors. Nobody chooses a score. The engine interprets the facts, identically every time: the same evidence always produces the same score. Scores run from 1 · Very easy to 5 · Very difficult, always shown as a number with its word label, never colour alone.

Decisive barriers are never averaged away

Some conditions decide a journey on their own: no step-free route, no lift to the destination, access that depends on another person responding. These are published as explicit barriers alongside the score, and certain combinations set a floor under it: a route cannot score “easy” while an unavoidable decisive barrier stands.

The publication gate

A score publishes only when all of the following hold: the route's applicable stages are covered by observed facts; at least one qualifying evidence event supports it: a verified visit (live photograph bound to the location and the reporting session), a professional survey, or partner-attested operational data; every scored stage is supported by evidence from someone who actually reached that part of the route; decisive barriers are verified; and no unresolved contradiction exists between reports. Until then the route says exactly where it stands: not enough information yet, awaiting verified evidence, or information under review.

Verification

A report becomes a verified visit when its photograph is captured live during the report, carries the device's location at capture, sits within tolerance of the building, and is not a duplicate of an existing image. Verification is probabilistic, never absolute, and photographs are stored privately for moderation, never published. Anonymous reports are accepted but can never raise a route's confidence; moderators can exclude any observation, and if support for a published score is withdrawn, the score is withdrawn with it.

Where evidence comes from

Every piece of qualifying evidence carries one of three provenance classes, named the same way everywhere they appear. Live verified visits are reports made in person through this platform, with a live location-bound photograph; they are currently the only evidence in the production database, so every published score is generated by the new platform. Partner-attested operational evidence is structured operational data supplied and formally attested by an organisation that visits the location for a living; it qualifies only under a named attestation, can never alone raise confidence to High, and none exists in production yet. Imported historical evidence refers to records from the original SARScore: they are archived privately as proof the concept works, and are never included in production scores, metrics, search results or maps. If an imported record is ever displayed in a demonstration context, its evidence date reads “imported; observation date not independently verified”, because an import date is not an observation date.

Confidence and freshness

Confidence reflects how much independent, qualifying evidence agrees: one verified visit alone is capped at Medium; High requires either multiple independent qualifying events or an audited professional survey; conflicting evidence caps confidence at Low and blocks publication. Freshness is reported separately: when the route was last verified is stated plainly, and verified freshness only moves on qualifying evidence, never on unverified activity.

Estimates are not scores

Where preliminary, unverified information exists, SARScore may show an estimate, clearly labelled, visually neutral, never wearing the score's colours or badge, and never for operational reliance. The distinction is enforced in the product, not just promised.

Temporary conditions

A broken lift is not a property feature. Temporary conditions are recorded separately, shown separately, expire or resolve on their own track, and can place a route under review, without rewriting its permanent record.

The evidence record

Observations are append-only: they can be excluded from scoring by moderation, but never edited or deleted. Every published score is an immutable snapshot carrying its inputs' summary, its methodology version and its calculation time, so any score can be explained, and history cannot be quietly rewritten.

Data sources and boundaries

Address identity comes from Ordnance Survey's national address register (Contains OS data © Crown copyright and database rights 2026). Community mapping context (© OpenStreetMap contributors; Overture Maps Foundation) may be displayed as unverified context, and is never part of a score. The scoring pipeline consumes only observed evidence: machine data suggests, humans observe, the engine decides.

Questions the page doesn't answer? See the FAQ or ask directly: hello@sarscore.com.