Glossary · Evaluation & safety
Exact Match (EM)
A metric that counts an output as correct only when its normalized representation exactly equals an accepted reference answer.
Why it matters
It is deterministic and easy to audit for tasks with one canonical answer, but it exposes no partial credit.
In practice
Define normalization and all accepted references before evaluation, then pair exact match with task-specific checks when several outputs can be valid.
Common confusion
A low exact-match score can reflect harmless formatting differences, while a matching string can still be unsupported or unsafe in context.
Related terms
Sources
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