Using Wikidata to find duplicates in the Library of Congress Name Authority File (LCNAF)

Abstract

The Library of Congress Name Authority File (LCNAF) has few automated systems to protect against the creation of duplicate authority records, and even fewer to detect them. In February 2026, as part of the Program for Cooperative Cataloging’s (PCC) new Entity Management Cooperative (EMCO), a group of cataloging and metadata librarians created a project to surface and resolve duplications in the LCNAF using Wikidata. Inspired by Wikidata’s constraint violation reports, they created SPARQL queries that returned all Wikidata items that had one or more LCNAF identifiers attached to them. They used these results to improve items that intentionally had two or more valid identifiers (such as pseudonym records) and resolved items that had duplicate LCNAF records by reporting them for deletion to the Library of Congress. Over the course of 6 months, the project improved the modeling of 1,559 Wikidata items and reported 166 LCNAF records for deletion. This unconventional strategy to improve data quality may interest technical services librarians working in systems that are represented in Wikidata.