During which site visits are the majority of case report form (CRF) data verified against source record information?

The majority of case report form (CRF) data verification against source record information occurs during periodic site visits. These visits are scheduled regularly throughout the course of a clinical trial to review and ensure accuracy in the collected data. During these visits, clinical research associates (CRAs) perform on-site monitoring to check that the data reported in the CRFs corresponds with the actual source documents, such as patient medical records. This process helps to ensure data integrity and compliance with the trial protocol.

In contrast, termination site visits typically focus on closing out the study and ensuring that all documents and data are properly finalized and that no outstanding issues remain. Site initiation visits are primarily aimed at training staff and preparing the site for the trial, rather than conducting extensive data verification. Prestudy site visits are generally conducted prior to the study initiation to assess the site’s readiness and capabilities rather than involving detailed data verification activities. Thus, periodic site visits are most critical for comprehensive data verification processes throughout the study.