Item 34 — Clinical trial registration
The International Committee of Medical Journal Editors (ICMJE) recommends that all medical journals require registration of clinical trials in a public trials registry at or before the time of first patient enrollment as a condition of consideration for publication. Registering the study protocol in a clinical trial registry, such as ClinicalTrials.gov or WHO Primary Registries, helps avoid overlapping or redundant studies and allows interested parties to contact the study coordinators.
Explanation and Elaboration: Clinical trial registration promotes research transparency and quality. Requiring investigators to publicly state their study’s primary and secondary outcomes in advance reduces the risk of unethical selection and publication of only favorable outcome measures (“cherry-picking”). Registration provides a public record of trials with unfavorable results: such work might not be published otherwise (the “file drawer” problem), enabling assessment of the extent to which publication bias may be affecting a scientific question. Registration statements enable readers to verify that the reported investigation was carried out as planned.