A source in the record states this causal link — a finding, a filing, an official account.
The definition the product enforces, read from the same code the methodology page renders.
A source in the record states the causal link itself, not just the two events. This is the top rung, and it says nothing about strength: a documented link can be a minor one. Read the strength beside it separately.
How a cause-and-effect link is KNOWN, kept apart from how much it matters. A documented link can be weak; a strong link can be inferred.
Every grade here is assigned by the same rules on every scan, and the methodology page renders those rules from the code that enforces them.