An evaluation of PubMed Central as a resource of free full-text articles for systematic reviews in biomedical research and education

BACKGROUND: PubMed Central (PMC) is a freely accessible digital repository offering full-text biomedical literature with structured metadata. Despite its scale, its suitability as a resource for systematic reviews, particularly in medical research and education, remains underexplored. METHODS: We studied the proportion of systematic reviews using PMC compared to other resources. Additionally, we examined the number of results retrieved by search strategies in PMC compared to PubMed in three random samples of subject topics (10 of 28 of the general and 25 of 413 of the extensive contents of the "Goldman's Cecil Medicine, 26th Edition" textbook, and 25 of 502 of the essential medicines listed in the "World Health Organization Model List of Essential Medicines"). RESULTS: About 0.5% of 407 242 systematic reviews archived in PubMed included PMC in the title and/or abstract, a considerably lower proportion compared to other resources (36%, 33.9%, 30.4%, 18%, 14.1%, and 5.8% for PubMed, Embase, Cochrane Library, Web of Science, Scopus, and Google Scholar, respectively). Even though PMC includes a considerably smaller number of articles than PubMed (11 vs. 39 million), the yield from PMC was higher compared to PubMed in the studied random samples [in 9/10 (90%), 21/25 (84%), and 25/25 (100%) of subject topics]. DISCUSSION: PMC is rarely utilized for systematic reviews. Although the number of articles retrieved from PMC is higher than PubMed, further studies should evaluate the comparative relevance of their yield, as PMC may return fewer specific articles on the studied research topic due to its inclusion of full-text articles. Key messages What is already known on this topic PubMed Central (PMC) is a free resource of full-text articles in biomedical fields. What this study adds Our study shows that PMC is rarely used as a resource for full-text articles for systematic reviews in biomedical research and education. In all three random samples of clinical medicine subjects that we studied, the yield of articles was higher in PMC than in PubMed. How this study might affect research, practice, or policy Future studies should focus on the relevance (specificity) of the yield of articles from PMC searches in specific research topics in systematic reviews.