principal investigator

The term principal investigator (PI) generally refers to the leader of the "science side" of a scientific research project. Such a PI is a scientist who is active in the field of study, with the knowledge to understand the project's methods and goals, and who assumes a leadership role in carrying out the project. For funded research, the term is generally used for the person who takes direct responsibility for the project's accomplishment. The project could be a NASA scientific mission, or the development of a research telescope or instrument, or a funded astronomical survey. Universities often define a principle investigator role for their major research projects.