Study Documentation: Source Data Verification

4. Source Data Verification

The study monitor has to compare the content of the CRFs with the content of the source documents. This is called ‘source data verification’. The monitor also checks if all the required data of the participant is present in the CRF entries, and that data is consistent with the source documents.

Previously, the rule was that 100% of all CRF entries were to be compared with the source data. Nowadays, the intensity of source data verification can be reduced. The concept of ‘risk-based monitoring’ allows the sponsor to decide to which degree the monitor needs to check individual types of data. Typically, the data that is checked most thoroughly is:

The signed Informed Consent documentation (often called Informed Consent Form – ICF).
The measurements that are most critical for answering the study’s scientific question(s).
The adverse events.
The inclusion/exclusion criteria adherence.