Provenance first
Before evidence can support a conclusion it must carry its own history: which system produced it, when, under what collection conditions, and whether it has been transformed since.
Four properties that determine weight
Weight is not a property of a data source in general. It is a property of a specific item of evidence in relation to a specific claim.
- Reliability: the historical accuracy of the source for this class of claim
- Freshness: whether the observation still describes the current state
- Independence: whether two supporting items share a common origin
- Corroboration: whether independent sources agree, and where they conflict
Contradiction is information
When two sources disagree, the disagreement itself is often the most valuable signal in the incident. Systems that silently pick a winner destroy that signal. Systems that surface and score it give the analyst the fastest path to the truth.