Independent sources
1 source — uncorroborated
2 sources
3 sources
4 or more sources
Counted by publisher, not by post — the same story reprinted is one source.
More sources means more reason to check, not that it is true.
Admiralty grading
A–F source reliability (A completely reliable … F cannot be judged)
1–6 information credibility (1 confirmed … 6 cannot be judged)
Graded automatically from source type and corroboration — e.g. F2 is an unknown
account whose report several independent publishers echo. Grade 1 (confirmed)
is never assigned by this tool: confirmation is a human decision.
Groups to check, most corroborated first