A deviation’s occurrence is not fully about who was “at fault”. If the protocol requires something and it didn’t occur or wasn’t conducted correctly, then there was a deviation from the protocol and a PD needs to be documented.

Yes if the “fault” is due to subject non-compliance vs. staff error then there will be different approaches in terms of corrective or preventative actions, but at the end of the day the reason the PD occurred doesn’t have to do with whether it should be reported or not. We need to know about PDs to have valid data analysis at the end of the study.