Both. They occur for any of the following reasons:
- to verify data that has been submitted to the agency
- if any complaints have been submitted in regard to that particular investigational site
- if any sponsors have concerns
- upon termination of the clinical site
- to provide real-time assessment of the investigator’s conduct of the trial and protection of human subjects during an ongoing trial
- at the request of an FDA review division
- for trials that are being conducted on investigational products that have been identified as a product of special interest
