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Knowledge Source

A Knowledge Source represents an authority for a Decision or Business Knowledge Model. It answers the question auditors ask first: who says this rule is correct?

Unlike every other node in a Decision Requirements Diagram, a Knowledge Source carries no executable logic. It is a citation.

Semantics​

  • Authority: It denotes where the knowledge comes from, for example "Loan Policy Documents", "Compliance Rulebook", or "Directive 2016/97 Art. 20".
  • Documentation Only: In QuantumBPM, Knowledge Sources are informational. They do not contain executable logic and do not affect the output of a decision.
  • No variable: Because it is never evaluated, a Knowledge Source does not define a variable and cannot be referenced from a FEEL expression.

Visual Representation​

In a DRD, a Knowledge Source is drawn as a wave-bottomed rectangle. It connects to a Decision or BKM with a dashed authority requirement arrow, pointing from the source to the element it governs.

An authority requirement is not a data dependency. Evaluation order is unaffected, and a Decision with no other inputs is still a leaf node even when a Knowledge Source points at it.

XML Serialization​

The node itself and the link to the element it governs are serialized separately:

<knowledgeSource id="ks_loan_policy" name="Loan Policy 2026" />

<decision id="d_loan_approved" name="Loan Approved">
  <authorityRequirement id="ar_1">
    <requiredAuthority href="#ks_loan_policy" />
  </authorityRequirement>
  <!-- decision logic omitted -->
</decision>

A BKM uses the same authorityRequirement child element. One Knowledge Source can govern any number of decisions, and a decision can cite several sources.

When to use one​

Knowledge Sources earn their place in regulated domains, where the useful question is not what a rule computes but which external document it implements:

  • Traceability: An underwriting decision table cites the policy version it encodes, so a reviewer can compare the two.
  • Change impact: When a regulation is revised, the authority requirements tell you which decisions to revisit.
  • Ownership: The source names the team or body that owns the rule, which is rarely the team that models it.

If none of those apply, the node is noise. A decision whose logic is self-evident does not need a citation, and adding one to every element makes the diagram harder to read without making it more auditable.

tip

Put the document version in the name, not just the title. "Credit Policy" ages badly; "Credit Policy v4 (2026-01)" tells a reviewer whether the model is current.