Meta-analysis has become a common approach to summarize genetic association with the tremendous amount of published epidemiological evidence. Assessing the credibility of meta-analysis evidence on genetic association is a rapidly growing challenge. This paper illuminates how to assess the credibility of meta-analysis evidence by using Venice criteria. A semi-quantitative index assigns three levels for the amount of evidence, replication and protection from bias. At the end, three considerations are merged into a grading scheme, which generates three composite assessments: weak, moderate or strong. Credibility assessment is necessary to estimate whether a true genetic association exists. Such method provides indication for further study and is of clinical importance.
