Are these data real? Statistical methods for the detection of data fabrication in clinical trials.
OBJECTIVE
To test the application of statistical methods to detect data fabrication in a clinical trial.


METHODS
Data from two clinical trials: a trial of a dietary intervention for cardiovascular disease and a trial of a drug intervention for the same problem.


METHODS
Baseline comparisons of means and variances of cardiovascular risk factors; digit preference overall and its pattern by group.


RESULTS
In the dietary intervention trial, variances for 16 of the 22 variables available at baseline were significantly different, and 10 significant differences were seen in means for these variables. Some of these P values were extraordinarily small. Distributions of the final recorded digit were significantly different between the intervention and the control group at baseline for 14/22 variables in the dietary trial. In the drug trial, only five variables were available, and no significant differences between the groups for baseline values in means or variances or digit preference were seen.


CONCLUSIONS
Several statistical features of the data from the dietary trial are so strongly suggestive of data fabrication that no other explanation is likely.
Al-Marzouki
Sanaa
S
Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London WC1E 7HT.
Evans
Stephen
S
Marshall
Tom
T
Roberts
Ian
I
D000328:Adult; D002318:Cardiovascular Diseases / Q000517:prevention & control; D016009:Chi-Square Distribution; D002986:Clinical Trials as Topic / Q000592:standards* / Q000706:statistics & numerical data; D003625:Data Collection / Q000592:standards* / Q000706:statistics & numerical data; D003627:Data Interpretation, Statistical; D004032:Diet; D006801:Humans; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D011897:Random Allocation; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D015871:Scientific Misconduct / Q000706:statistics & numerical data*