Consistency of Medical Subject Headings assignment: A test-retest reliability analysis

Medical Subject Headings (MeSH) are the controlled vocabulary used by the National Library of Medicine (NLM) to index articles covered by MEDLINE.

Evaluate the consistency of MeSH assignment using a test-retest analysis of articles published multiple times.

Three sets of articles that had been published multiple times were selected: Vancouver Group articles, CONSORT Statement articles, and Granada Statement articles. The articles publishing these position papers were searched in PubMed in February 2025, and their records were exported in XML format. The articles' metadata, the assigned MeSH terms, and the indexing methods were extracted. Consistency was assessed using Fleiss' kappa for inter-rater agreement and Krippendorff's alpha for classification reliability, considering each article as a different rater.

A total of 6, 8, and 5 articles indexed in MEDLINE were retrieved that had published articles with Vancouver, CONSORT, and Granada statements, with 14, 6, and 10 different MeSH terms assigned, respectively. The first two sets of articles were manually indexed, while the Granada articles were automatically indexed. Fleiss' kappa for the MeSH terms assigned to the Vancouver, CONSORT, and Granada articles were -0.390, -0.370, and -0.333, respectively, and Krippendorff's alphas were 0.178, 0.525, and 0.183, respectively. "Periodicals as Topic" and "Randomized Controlled Trials as Topic" were used in all Vancouver and CONSORT articles, respectively. Except for "Humans," no other MeSH terms appeared in all Granada articles. The most prevalent terms were "Pharmacy" and "Pharmacies" and "Pharmacy Research." Geographic MeSH terms were assigned to the Vancouver and Granada articles.

A highly inconsistent MeSH indexing pattern was found across the three sets of articles. Automated indexing of the Granada Statements articles did not improve the results.