The requirements of authorities and company’s internal auditors for overview of patient safety and data quality rises with the number of subjects included in a study. According to ICH-GCP every clinical trial requires quality control for the information gathered, to ensure that they are reliable and have been processed adequately. It is only on the basis of accurate and complete data that correct conclusions can be generated.

Despite careful monitoring and detailed programming, it always remains discrepancies and erroneous information which cannot be cleared though algorithmic formulas. Such data inconsistencies can only be identified and corrected by medical judgment. This process of careful, mostly manual check is Medical Data Review.