“Who should identify the critical data/process for study? Should it be science?”
ICH GCP Ref: 5.0.1 ; 5.0.2 ; 5.0.3
Best practice would be for this step to also be a cross functional activity performed at the beginning of the risk assessment process. It is essential to have science involved but would not recommend this task is performed solely by science, or the protocol owner(s), as they have written the protocol it will be more challenging to remain objective, it is like critiquing your own work. The views of other parties can help to examine if data/process is truly essential to the study, or to evaluate if data/process is missing. If science initiates the process, other functions should have the ability to review and comment but would recommend it being cross functional activity.