Difficulty in detecting discrepancies in a clinical trial report: 260-reader evaluation

Abstract

Background: Scientific literature can contain errors. Discrepancies, defined as two or more statements or results that cannot both be true, may be a signal of problems with a trial report. In this study, we report how many discrepancies are detected by a large panel of readers examining a trial report containing a large number of discrepancies.

Methods: We approached a convenience sample of 343 journal readers in seven countries, and invited them in person to participate in a study. They were asked to examine the tables and figures of one published article for discrepancies. 260 participants agreed, ranging from medical students to professors. The discrepancies they identified were tabulated and counted. There were 39 different discrepancies identified. We evaluated the probability of discrepancy identification, and whether more time spent or greater participant experience as academic authors improved the ability to detect discrepancies.

Results: Overall, 95.3% of discrepancies were missed. Most participants (62%) were unable to find any discrepancies. Only 11.5% noticed more than 10% of the discrepancies. More discrepancies were noted by participants who spent more time on the task (Spearman's ρ = 0.22, P < 0.01), and those with more experience of publishing papers (Spearman's ρ = 0.13 with number of publications, P = 0.04).

Conclusions: Noticing discrepancies is difficult. Most readers miss most discrepancies even when asked specifically to look for them. The probability of a discrepancy evading an individual sensitized reader is 95%, making it important that, when problems are identified after publication, readers are able to communicate with each other. When made aware of discrepancies, the majority of readers support editorial action to correct the scientific record.

Keywords: Peer review; clinical governance; patient safety; retraction of publication.

Figure 1.

Spectrum of discrepancy recognition. For any research paper with discrepancies, this plot tests the hypothesis that each reader is capable of finding them on their own, and therefore does not need the discrepancies to be communicated via the journal. Each black area represents a detected discrepancy. Each of the 39 columns represents a different discrepancy and has been arranged by decreasing chance of detection by participants. Each of the 260 rows represents a participant and has been arranged from most successful in detecting discrepancies at the top to least successful at the bottom. If all readers were capable of detecting all discrepancies independently, the entire diagram would be black. The concentration of black areas in the top-left corner indicates that some discrepancies were much easier to find than others.