Intended for healthcare professionals


Catalogue of errors in papers reporting clinical trials

BMJ 2015; 351 doi: (Published 21 September 2015) Cite this as: BMJ 2015;351:h4843
  1. Nick Freemantle, professor of clinical epidemiology and biostatistics,
  2. Greta Rait, reader in primary care
  1. 1Department of Primary Care and Population Health, PRIMENT Clinical Trials Unit, UCL Medical School (Royal Free Campus), London NW3 2PF, UK
  1. Correspondence to: N Freemantle nicholas.freemantle{at}

Errors are linked to retraction, but are an unreliable marker for fraudulent or harmful research

The paper by Cole and colleagues1 examines the association between discrepancies and retractions in clinical trial reports, concluding that discrepancies or errors could be an early signal of unreliability in clinical trials. It is another foray by these authors into the examination of error in reported research. Their previous paper2 3 demonstrated a clear and concerning relation between error and inflated effect size in stem cell research. But is the identification of unreliable, misleading, or even fraudulent research really as simple as counting the number of errors or discrepancies in clinical trial reports? Cole and colleagues describe errors or discrepancies as red flags, but several limitations within their own study indicate that these red flags are an unreliable marker for deeper problems within a piece of research.

The authors undertake a case-control study and make recommendations based on sensitivity and specificity, even though they acknowledge that these metrics depend on prevalence and the research design is inappropriate.4 There are far more unretracted reports of clinical trials (802 953 papers on PubMed, 6 July 2015) than retracted reports of clinical trials (379 papers on same …

View Full Text

Log in

Log in through your institution


* For online subscription