How accurate are citations of frequently cited papers in biomedical literature?

Abstract

Citations are an important, but often overlooked, part of every scientific paper. They allow the reader to trace the flow of evidence, serving as a gateway to relevant literature. Most scientists are aware of citations errors, but few appreciate the prevalence or consequences of these problems. The purpose of this study was to examine how often frequently cited papers in biomedical scientific literature are cited inaccurately. The study included an active participation of first authors of frequently cited papers; to first-hand verify the citations accuracy. The approach was to determine most cited original articles and their parent authors, that could be able to access, and identify, collect and review all citations of their original work. Findings from feasibility study, where we collected and reviewed 1,540 articles containing 2,526 citations of 14 most cited articles in which the 1st authors were affiliated with the Faculty of Medicine University of Belgrade, were further evaluated for external confirmation in an independent verification set of articles. Verification set included 4,912 citations identified in 2,995 articles that cited 13 most cited articles published by authors affiliated with the Mayo Clinic Division of Nephrology and Hypertension (Rochester, Minnesota, USA), whose research focus is hypertension and peripheral vascular disease. Most cited articles and their citations were determined according to SCOPUS database search. A citation was defined as being accurate if the cited article supported or was in accordance with the statement by citing authors. A multilevel regression model for binary data was used to determine predictors of inaccurate citations. At least one inaccurate citation was found in 11% and 15% of articles in the feasibility study and verification set, respectively, suggesting that inaccurate citations are common in biomedical literature. The main findings were similar in both sets. The most common problem was the citation of nonexistent findings (38.4%), followed by an incorrect interpretation of findings (15.4%). One fifth of inaccurate citations were due to "chains of inaccurate citations," in which inaccurate citations appeared to have been copied from previous papers. Reviews, longer time elapsed from publication to citation, and multiple citations were associated with higher chance of citation being inaccurate. Based on these findings, several actions that authors, mentors and journals can take to reduce citation inaccuracies and maintain the integrity of the scientific literature have been proposed.