Publication bias was not a good reason to discourage trials with low power.
until further notice
SourceJournal of Clinical Epidemiology, 62, 1, (2009), pp. 47.e1-10
Article / Letter to editor
Display more detailsDisplay less details
Centre for Quality of Care Research
Epidemiology, Biostatistics & HTA
Journal of Clinical Epidemiology
SubjectIGMD 6: Hormonal regulation; NCEBP 1: Molecular epidemiology; NCEBP 2: Evaluation of complex medical interventions; ONCOL 2: Age-related aspects of cancer; ONCOL 3: Translational research
OBJECTIVE: The objective was to investigate whether it is justified to discourage trials with less than 80% power. Trials with low power are unlikely to produce conclusive results, but their findings can be used by pooling then in a meta-analysis. However, such an analysis may be biased, because trials with low power are likely to have a nonsignificant result and are less likely to be published than trials with a statistically significant outcome. STUDY DESIGN AND SETTING: We simulated several series of studies with varying degrees of publication bias and then calculated the "real" one-sided type I error and the bias of meta-analyses with a "nominal" error rate (significance level) of 2.5%. RESULTS: In single trials, in which heterogeneity was set at zero, low, and high, the error rates were 2.3%, 4.7%, and 16.5%, respectively. In multiple trials with 80%-90% power and a publication rate of 90% when the results were nonsignificant, the error rates could be as high as 5.1%. When the power was 50% and the publication rate of non-significant results was 60%, the error rates did not exceed 5.3%, whereas the bias was at most 15% of the difference used in the power calculation. CONCLUSION: The impact of publication bias does not warrant the exclusion of trials with 50% power.
Upload full text
Use your RU credentials (u/z-number and password) to log in with SURFconext to upload a file for processing by the repository team.