GCP has two important goals: protection of the subject, and protection of the data which is possible only through adequate training of all concerned staff. An independent audit is needed to ensure compliance to the standards. US FDA acts as enforcement officers. As they are less flexible unconventional approaches have no scope. European agencies are more flexible but they need to be convinced.
The Declaration of Helsinki issued by world medical association insists that all research subjects must be fully informed about the nature and risks of a clinical trial. Protocol design is a responsibility of the investigator and need to be assessed by the concerned ethical committee. The principal investigator has an overall responsibility over the entire project.
Informed consent which includes signing a consent form and a recruiting interview preferably by the physician is extremely important. Though not absolutely necessary it is a good practice to define and describe in writing how all aspects of clinical research are to be conducted. These standard operating procedures (SOPs) must be followed during the execution of the research.