Systematic review and meta-analysis of quotation inaccuracy in medicine

Quotations are crucial to science but have been shown to be often inaccurate. Quotation errors, that is, a reference not supporting the authors' claim, may still be a significant issue in scientific medical writing. This study aimed to examine the quotation error rate and trends over time in the medical literature.

A systematic search of PubMed, Web of Science, and reference lists for quotation error studies in medicine and without date or language restrictions identified 46 studies analyzing 32,000 quotations/references. Literature search, data extraction, and risk of bias assessments were performed independently by two raters. Random-effects meta-analyses and meta-regression were used to analyze error rates and trends (protocol pre-registered on OSF).

16.9% (95% CI: 14.1%-20.0%) of quotations were incorrect, with approximately half classified as major errors (8.0% [95% CI: 6.4%-10.0%]). Heterogeneity was high, and Egger's test for small study effects remained negative throughout. Meta-regression showed no significant improvement in quotation accuracy over recent years (slope: -0.002 [95% CI: -0.03 to 0.02], p = 0.85). Neither risk of bias, nor the number of references were statistically significantly associated with total error rate, but journal impact factor was: Spearman's ρ = -0.253 (p = 0.043, binomial test, N = 25).

Quotation errors remain a problem in the medical literature, with no improvement over time. Addressing this issue requires concerted efforts to improve scholarly practices and editorial processes.