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Principal Investigator

Principal investigator (PI) is the researcher responsible for the management, conduct, and reporting of a research project.


PI in clinical trials

In clinical trials the PI is the physician responsible for the conduct of a clinical trial at a trial site and who coordinates with the study sponsor as well as the Institutional Review Board (IRB).


PI responsibilities

The PI assumes the overall responsibility for all clinical research activities and ensures that the study is run in accordance with the requirements of the relevant regulatory agencies and the Guidelines for Good Clinical Practice. These responsibilities include:

  • Conducting and supervising the research activities, e.g. ensuring that the protocol is scientifically sound and of value and the facility is equipped (personnel, equipment, space, funding) to perform the research.
  • Obtaining all necessary approval, specifically IRB approval .
  • Select personnel that is qualifies and certified to perform the tasks they are assigned to during the trial.
  • Protect the rights, safety and welfare of the study participants e.g. by ensuring that the study is performed in accordance with all applicable regulatory requirements.


PI qualifications

In the US, the qualifications a PI must meet are defined in broad terms by the FDA which require that they must be qualified by training and experience. (1) In Europe the qualification standards for investigators vary between countries , e.g. GCP courses for investigators are mandatory in Germany, Hungary, Ireland, Norway, Portugal and Switzerland and are not mandatory in France and Spain, though GCP must be well known. (2)


PI in research

Research projects can also be run by a principal investigator. As in the case of a clinical trial PI, the research PI is responsible for coordinating and managing the research project, budgeting, reporting and any deliverables described in the (grant) proposal. This is relevant especially for larger projects that have several researchers who are contributing.