Assurance Claim

An Assurance Claim is an assertion claim about a property of a system that is stated within an assurance case.

• AKA: Assurance Case Claim.
• Context:
  • It can (typically) be a top-level claim, which the assurance case seeks to show is satisfied, or a subclaim, into which a higher-level claim decomposes.
  • It can (typically) concern an emergent property of the system, such as safety, security, resilience, reliability or survivability.
  • It can (often) be supported by an Assurance Argument that links it to Assurance Evidence Items and to explicit assumptions.
  • It can be stated as an assumption, declared axiomatic, marked as needing support, or recorded as defeated by counter-evidence, and it remains the same claim whatever that status.
  • It can turn out to be supported, not supported, or without sufficient basis either way: whether it is true, and whether its evidence is sufficient, are assessed separately from its being a claim.
  • ...
  • It can range from being a Top-Level Assurance Claim to being an Assurance Subclaim, depending on its place in the claim decomposition.
  • It can range from being a Security Assurance Claim to being a Safety Assurance Claim, depending on the property it addresses.
  • ...
• Example(s):
  • a Security Assurance Claim, such as the top-level claim that a system adequately contributes to freedom from the conditions that cause asset loss and the associated consequences.
  • a subclaim that a system's security policy is enforced as specified.
  • ...
• Counter-Example(s):
  • a Subjective Assertion Claim, such as a stated preference for one café over another, which is not about a property of a system and is not stated within an assurance case.
  • an Assurance Evidence Item, which bears on a claim but is not itself a claim.
  • an Assurance Argument, which links evidence and claims rather than asserting a property.
  • ...
• See: Assertion Claim, Assurance Argument, Assurance Evidence Item.

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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, the property scope and the claim decomposition: an assurance case is "a reasoned, auditable artifact that is created to support the contention that a top-level claim is satisfied" and contains "One or more claims about properties"; assurance cases are "used to demonstrate that a system exhibits some complex emergent property, such as safety, security, resilience, reliability, or survivability"; "Top-level claims decompose in a structured manner into subclaims"; from a security perspective, a top-level claim is that "the system will adequately contribute to freedom from the conditions that cause asset loss and the associated consequences"; and evidence "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".
• Object Management Group. (2022). Structured Assurance Case Metamodel (SACM), Version 2.2. Retrieved 2026-10-15. Supports the claim statuses: "Claims are used to record the propositions of any structured argument"; a claim "intentionally declared without any supporting evidence or argumentation can be declared as being assumed"; a claim can be declared "axiomatic", "needsSupport" or "defeated" ("defeated by counter evidence or counter argument").