A Columbia University-led study reports that fabricated references are increasingly appearing in scholarly papers, with the rate climbing from four per 10,000 papers in 2023 to 51.3 per 10,000 by the end of 2025. Researchers led by healthcare AI scientist Maxim Topaz published findings in the Proceedings of the National Academy of Sciences, analyzing five research areas—biomedical research plus physics, computer science, materials science, engineering, and chemistry. Using OpenAlex to sample 500,000 studies (January 2023 through March 31, 2026) and applying DOI- and title-matching checks supported by a large language model, the team evaluated 21.6 million references and identified 1,135 as likely fabricated across 619 papers. The authors said publishers and the research community need faster methods to detect and remove invalid sources, as the problem expands beyond a single subfield.