An investigator is a person responsible for the conduct of the clinical trial, including responsibility for the trial participants during the conduct of the trial. When a team conducts the trial, the responsible leader is called the Principal Investigator, often abbreviated as PI. The investigator is typically a physician, though depending on the research, they might be a dentist, psychologist, or other qualified professional.

The key word is "responsible." The investigator does not do everything personally, but they are accountable for everything that happens at their site.

An investigator is a person responsible for the conduct of the clinical trial, including responsibility for the trial participants during the conduct of the trial. When a team conducts the trial, the responsible leader is called the Principal Investigator, often abbreviated as PI. The investigator is typically a physician, though depending on the research, they might be a dentist, psychologist, or other qualified professional.

The key word is "responsible." The investigator does not do everything personally, but they are accountable for everything that happens at their site.