Home > TRAK Metamodel Features > Claim, Argument and Evidence Tuples

Claim, Argument and Evidence (CAE) Tuples

Part of the TRAK Metamodel provides a way to describe Claims, Arguments and Evidence. This is typically used in assurance, for example, to describe how and why a requirement is met and how the design supports this. The application areas are therefore:-

• design verification or assurance
• safety assurance cases
• security assurance - to describe how the proposed design addresses threats (hazards) and mitigates the risks

TRAK Metamodel Tuples Involving Claim, Argument and Evidence

Establishing the Claim

The tuples that the TRAK metamodel provides to describe the Claim are:-

• the source that makes the Claim:
  • Organisation makes Claim
  • Role makes Claim
• the object of the Claim:
  • Claim about a single element
    • Claim about Architecture Description Element (where Architecture Description Element = any element allowed in a TRAK view)
    • Claim about Contract, Requirement or Standard
    • Claim about System
    • Claim about Organisation
    • ...
  • Claim about an assurance assertion - itself a triple:
    • Claim about (Software satisfies Standard)
    • Claim about (Standard satisfies Contract)
    • ...
• the Claim structure:
  • Claim has part Claim
  • Claim supports Claim
  • Claim opposes Claim (to describe a counter-claim)

Where the object of the Claim is a triple the result is termed an n-ary triple.

TRAK Metamodel Provides N-Ary Triples That can be Used to Describe Assurance Assertions

Structuring the Argument

The tuples that the TRAK metamodel provides to describe the Argument are:-

• Argument supports Claim
• Argument opposes Claim
• Argument has part Argument
• Argument supports Argument
• Argument opposes Argument (to describe a counter-Argument)
• Architecture Description Element traces to Argument (to show where the structure or relationship is a result of an Argument made)

Identifying Supporting Evidence

The tuples that the TRAK metamodel provides to describe the Evidence are:-

• Evidence supports Argument
• Evidence opposes Argument
• Evidence has part Evidence

and then if the Claim - Argument - Evidence chain is accepted by the assurer or regulator this can be recorded using:

• Evidence proves Claim or
• Evidence disproves Claim

Note that the proves and disproves connectors both have attributes to record the assessment result and date of submission.

Applicable TRAK Architecture Viewpoints

The applicable TRAK architecture viewpoints are:-

• MVp-04 Assurance - to describe the claim, argument and evidence
• MVp-03 Requirements & Standards - to describe the normative requirements from specifications, contracts, statutes (and what they govern)