False negative
Also: false negatives
Something the system missed that it should have found.
The fuller definition
A false negative is an item that meets the target condition but is missed or classified as negative.
The reference set has ten relevant events. Six are found, four are missed, and two additional returned items are unsupported. This example measures extraction, not every aspect of a legal work product.
A concrete example
A search omits a relevant email because it uses different wording from the query.
The distinction that matters
You need coverage checks or a reference set to discover omissions that are invisible in the returned output.
Related terms
Recall
Of the things it should have found, how many it actually found.
Reliability & securityFalse positive
Something the system flagged that it should not have.
Documents & retrievalRetrieval
Searching a larger set of records for useful parts. Finding a passage does not prove it answers the question.
Where it is taught
Test an AI workflow on work you can assessSource and further reading
Anthropic · Evaluating AI agentsThe definition and example are written for this library. The link gives background, official documentation or legal authority as labelled. Legal scope depends on the jurisdiction and current text; product features depend on release and settings.