---
title: "Evidence and Claim Glossary | Witnessability"
description: "Plain-language explanations of claim, evidence, appraisal, producing boundary, independence and related Witnessability terms, with links to source texts."
canonical: "https://witnessability.io/glossary/"
representation: "Website reading format; consult linked publications for their exact status and terms."
---

[Witnessability](https://witnessability.io/) / Reference / Plain-language terms

# A vocabulary for precise conclusions

These short explanations help you read the site. Definitions in a cited specification apply within that document's own scope and version. This glossary does not replace them or create a new standard.

Witnessability editorial explanation · 30 October 2026\
Prepared with AI assistance. [Authorship and responsibility](https://witnessability.io/about/#authorship).\
Read the linked publications for their exact definitions and status.

## Witnessability

The claim-relative capacity to produce, preserve and expose evidence and reasoning for evaluation and challenge. The Conceptual Core gives the formal definition; this is a reading aid.

## Claim

A statement offered for someone to rely on. State its exact subject, scope and time. An assertion about execution differs from one about authorization or a later effect.

## Evidence

Material offered in support of a claim, such as a record, observation, receipt or proof. Calling material evidence does not establish that it supports the particular claim.

## Producing boundary

The vantage point, component or interface where evidence was produced, considered together with what it could observe and who controlled it.

## Claim ceiling

A limit on claims of a specified kind that a boundary's evidence can support under stated premises. It excludes unsupported extensions; it does not create positive evidence.

## Appraisal

Assessment of what identified evidence supports about a specified claim under stated premises. Preserve the evaluator, the evidence basis and the context when reusing its result.

## Relying party

The person or organization deciding whether to accept a claim. Its decision may depend on policy or risk requirements beyond the evidentiary assessment.

## Independence

A control relationship stated relative to a party, capability, period and threat model. Different keys or organizational labels alone do not establish resistance to forgery, concealment or circumvention.

## Invocation and execution

Invocation concerns an exact request crossing an observed boundary. Execution concerns performance evidenced at an appropriate boundary. Neither automatically establishes completion of a larger process or a durable external effect.

## Assessment status and finding

CBEE distinguishes evaluated from not evaluated. When assessed, a claim may be supported, unsupported by the evaluated evidence, or refuted by evidence for its negation. These distinctions must not be collapsed.

## Unverifiable

In CBEE, a reason for not evaluated: this evaluator cannot check the statement with the available inputs at the relevant time. It is not a permanent property of the statement.

## Coverage

The declared scope within which relevant events or records are accounted for. Authenticity of individual records alone does not establish completeness of the collection or observation regime.

## Sources and next steps

- [Witnessability Conceptual Core 1.0](https://witnessability.io/core/1.0/)
- [CBEE revision 02](https://datatracker.ietf.org/doc/draft-sergeev-claim-boundaries/02/)
- [CBEE reading copy: terminology](https://github.com/Witnessability/cbee-spec/blob/main/review/editor-copy.md#terminology)

## What this does not claim

These terms are contextual explanations, not interchangeable labels across all standards. In particular, CBEE's reporting distinctions are not a universal result-code set or a single scale of assurance.