Evidence ladder

Use the strongest evidence practical for the decision. A higher class can still be stale, irrelevant, or too broad for the nearby claim.

Direct current observation — reproduced behavior, command output, inspected artifact, or measured result.
Authoritative primary source — official specification, dataset, law, documentation, first-party repository, or original research.
Independent corroboration — competent sources with distinct underlying evidence.
Explicit inference — a conclusion whose premises and assumptions are visible in the map.
Weak proxy — related metric, benchmark, anecdote, or test that does not exercise the exact claim.
Unsupported assertion — confidence, repetition, or polished language without evidence.

Source-region test

Before creating an evidence node, answer:

What exact sentence, table, command output, page, section, or line range is being relied on?
Does it entail the node text, or merely discuss the same subject?
Is its date and version appropriate for the claim?
Is the evidence independent, or copied from another cited source?
What context would reverse or narrow the interpretation?

If the exact region cannot be located, create an unknown node instead of an evidence node.

Relation	Use when	Common counterfeit
`supports`	The source increases reason to accept the target	Topical similarity
`contradicts`	Both cannot hold under the same scope and conditions	Different dates or populations
`qualifies`	The source narrows scope, strength, or applicability	Hiding inconvenient evidence
`missing`	A specific absent fact blocks or could reverse the target	Generic “more research needed”