Assurance Evidence Item

An Assurance Evidence Item is an evidence item that bears, for or against, on one or more agreed assurance claims.

• AKA: Assurance Evidence.
• Context:
  • It can (typically) be obtained directly through measurement, testing, observation or inspection, or indirectly through analysis of data obtained in those ways.
  • It can support a conclusion that a claim is achieved, that it is not achieved, or that there is not enough basis to decide either way.
  • It can (typically) be checked for accuracy, credibility, relevance, rigor and quantity before it is used.
  • It can be recorded in a document, record or test report that carries the information.
  • It can be relevant to one agreed set of claims and not to another: its evidential role is relative to the claims it bears on.
  • ...
  • It can range from being a Direct Assurance Evidence Item to being an Indirect Assurance Evidence Item, depending on whether it was obtained directly or through analysis.
  • It can range from being Affirming Evidence to being Rejecting Evidence for a given claim.
  • ...
• Example(s):
  • a penetration-test result cited for a claim that an interface resists unauthorized access.
  • a static-analysis report cited for a claim that a component is free of buffer overflows.
  • a design-inspection record cited for a claim that a security policy is enforced as specified.
  • ...
• Counter-Example(s):
  • a legal evidence item offered solely in a dispute and unrelated to any agreed assurance claim.
  • a file submitted with an assurance case that does not bear on any of its claims.
  • an Assurance Claim, which evidence bears on but which is not itself evidence.
  • ...
• See: Evidence Item, Assurance Argument, Assurance Claim.

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References

2022

• Ross, R., Winstead, M. & McEvilley, M. (2022). Engineering Trustworthy Secure Systems, NIST Special Publication 800-160 Volume 1, Revision 1. Retrieved 2026-10-15. Supports the definition and the Context on how it is obtained, checked and scoped, and on negative findings: assurance evidence is "The information upon which decisions regarding assurance, trustworthiness, and risk of the solution are substantiated", and "Assurance evidence is specific to an agreed-upon set of claims"; it "can be obtained either directly through measurement, testing, observation, or inspection or indirectly through analysis"; "Evidence must have sufficient quality in accuracy, credibility, relevance, rigor, and quantity"; and it "can support a conclusion that a stated claim is not achieved or that there is an insufficient basis to conclude that the claim is supported or not supported".