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Document Duplicity Check

Document duplicity check finds duplicates by the data on the document — name, date of birth, personal number, document number — rather than by face. It catches people re-registering under the same identity details and provides the text signal that complements face duplicity check.

Document duplicity check requires the Data Storage tier but, unlike face 1:N, does not require the biometric 1:N add-on — it is a text search over existing Customer records.

1:1 Document Compare​

In order to decide, whether 2 documents are of a same person, rules for comparison need to be defined. Different countries may have different conventions for giving a name and may have different personal identifiers. Thus, each integration may have different comparison rules.

What is compared​

The integrator needs to define, which fields are compared, and how the different comparison scores are weighted to create one matching score that is compared against a threshold.

StrengthFields
Strong (identity anchors)Date of birth, personal number
SupportingFull name, given names, surname, document number

How matching works​

  1. Text cleaning — names are normalized (titles stripped, lower-cased, punctuation removed) so cosmetic differences don't cause misses.
  2. Similarity scoring — names are compared with a fuzzy string-similarity measure that tolerates typos and minor spelling variation; exact fields like date of birth and personal number act as strong anchors.
  3. Weighted score — the platform combines the field scores into a single weighted score and compares it against a match and a similar threshold. The comparison fields, their weights, and the thresholds are configurable per tenant.

Outcomes​

ResultMeaning
No matchNo existing record shares the document data.
Similar matchA record is close (e.g. same DOB, near-identical name) — warrants review or cross-checking against the face.
Full matchA record shares the strong identity fields.

1:N Identification​

Identification search the new applicant's document data against all existing Customers. First, the search narrows the candidate records, then the shortlist is re-scored using the 1:1 matching rules.

Combining document match with a face match​

The real value comes from cross-checking the document signal against the face signal — a full text match with a non-matching face is a classic stolen-ID pattern, while a matching face with different text can indicate a name change or a fabricated document. See the disambiguation matrix in Identity Verification.

See also​