nonmatch

Nonmatch is a term used to indicate that two items do not correspond in a comparison. It is used in fields that involve matching, verification, and search, including data processing, biometrics, and cataloging. A nonmatch typically signals that the items being compared fail to meet a required level of similarity or alignment, and may lead to further action such as review, retries, or alternative handling.

In data matching and record linkage, a nonmatch is identified when two records do not refer to the same entity. This outcome contrasts with a match, where records are deemed to represent the same object. Nonmatches are common in deduplication, data cleansing, and search queries, and may be logged for audit purposes. Similarity scores below a chosen threshold often trigger a nonmatch designation.

In biometrics and identity verification, a nonmatch result occurs when the presented sample does not match the enrolled template. Nonmatches support rejection decisions in authentication workflows and may prompt a retry, secondary verification, or a security alert.

In cataloging, inventory, and document verification, nonmatch indicates discrepancies between attributes such as identifiers, names, or addresses, suggesting errors, outdated information, or the need for manual verification.

The term is usually hyphenated as non-match in technical writing, though some sources use nonmatch or not a match. Its precise meaning depends on context, threshold settings, and workflow design. Related concepts include mismatch, no match, and the broader idea of record linkage or similarity assessment.