Abstract
Prevalence of the Statement “to Our Knowledge” and Similar Paraphrases in Current and Past Biomedical Literature
Nicola Di Girolamo,1,2 Reint Meursinge Reynders,3,4 Ugo Di Girolamo5
Objective
Statements like “to our knowledge, this is the first time that” are ambiguous,1 but are often used when describing a potential novel aspect of an article, often in lieu of a literature search.2 Although seemingly innocuous, similar paraphrases lack reproducibility and accountability. This study assessed the prevalence of the statement “to our knowledge” (TOK) in the biomedical literature and in leading medical journals in the past 75 years as well as before and after implementing an intervention to reduce such prevalence in 2 journals.
Design
Full texts of articles available in PubMed Central (PMC) were searched using PMC’s phrase index for paraphrases of the statement TOK. Prevalence was measured in articles available in PMC published by 6 leading medical journals (The Lancet, NEJM, The BMJ, JAMA, Ann Int Med, PLOS Medicine) and in all articles in PMC in 2 time periods: January 1950 to December 2019 and January 2020 to December 2024 by 1 author (N.D.G.). To evaluate the search strategy, all articles published in 2024 in The Lancet with full text available in PMC (N = 43) were manually screened for TOK and compared with results of the engine search. To evaluate how often TOK was reported, all The Lancet research articles published in 2024 (N = 166) were manually screened. In 2 journals, Journal of Small Animal Practice (JSAP) and Journal of Exotic Pet Medicine (JEPM), an intervention to advise authors against use of these phrases and in favor of a scoping search of the literature was implemented in 2020, and TOK prevalence was measured in 2018 and 2024.
Results
Among 4488 articles available in PMC published in 6 leading medical journals in 2020 to 2024, the prevalence of TOK was 21.7% (974), highest in PLOS Medicine (48.4%) and lowest in NEJM (1.3%) (Table 25-1191). Prevalence among these journals was 5.7% (95% CI, 4.5%-6.9%) higher than all journals included in PMC. Compared with articles published in 1950 to 2019, prevalence of TOK in the last 5 years increased 8.2% (95% CI, 6.9%-9.6%) in leading medical journals and 3.1% (95% CI, 3.1%-3.2%) in all PMC journals. The search strategy had a sensitivity of 66.7% (95% CI, 34.9%-90.1%), a specificity of 100.0% (95% CI, 88.8%-100.0%), and an overall accuracy of 90.7% (95% CI, 77.9%-97.4%). In the manually screened articles, TOK was mentioned 5 times in 1 article (0.6%), 3 times in 6 articles (3.6%), 2 times in 17 articles (10.2%), and 1 time in 57 articles (34.3%). In JSAP and JEPM, TOK prevalence in articles decreased from 37.4% to 7.6% after the intervention.
Conclusions
Paraphrases of TOK have been highly prevalent in the biomedical literature for the past 75 years and continue to be prevalent, including in leading medical journals. A simple intervention can decrease the use of this statement. This study is limited to only the portion of articles available in PMC, does not include all articles published by the 6 leading medical journals, and does not differentiate between version types (eg, accepted manuscript, published article) or article types (eg, research, review, or opinion).
References
1. Vaisrub S. To the best of our knowledge, which is limited at best. JAMA. 1979;241(3):278.
2. Di Girolamo N, Meursinge Reynders R. On “authors’ knowledge” and contrast-enhanced ultrasonography in rabbits. Vet Radiol Ultrasound. 2019;60(4):371.
Affiliations
1Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, US, nd374@cornell.edu; 2Journal of Small Animal Practice, British Small Animal Veterinary Association, Gloucestershire, UK; 3Department of Oral and Maxillofacial Surgery, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, the Netherlands; 4private practice of orthodontics, Milan, Italy; 5Compass, New York, NY, US.
Conflict of Interest Disclosures
Nicola Di Girolamo was an editor in chief of 2 peer-reviewed journals at the time of submission, 1 published by Elsevier and 1 by Wiley. The other authors declare no competing interests nor conflicts of interest.