Research and Scholarship FAQs

Differences between a PD/PI, Multiple PI, a Co-PI, & a Co-Investigator

USF Information on the Roles and Responsibilities of PIs and Co-PIs

Information on the roles and responsibilities of PIs and Co-PIs can be found in the USF Roles and Responsibilities policy. See also USF’s Guidelines to Determine PI Eligibility.

As described in the policies, all USF tenured, tenure-track, and non-tenure track faculty, researchers and scholars may serve as a Principal Investigator (PI) on a proposal for external funding.

While post-doctoral scholars and adjunct faculty may serve as Co-principal Investigators (Co-PI) on sponsored projects, they may not serve in the role of PI unless pre-approved by USF’s Sponsored Research in collaboration with the appropriate responsible officer (College and/or Campus Dean, Director, or Vice President). Pre-approval is required for each proposal.

A request for exception to the guidelines must be submitted in writing to the Director of Sponsored Research by the appropriate Department Chair, signed by the College and/Campus Dean (or designee), and accompanied by the appropriate biosketch (NIH or NSF format) no later than two weeks before the proposal deadline.

Note: USF currently has no eligibility requirements for Co-PIs, provided a PI-eligible PI is in place, and the Co-PI meets eligibility requirements imposed by the sponsor.


Principal Investigator (PI) identifies the individual responsible for activities on a research project or activity, particularly those funded by a grant, a cooperative agreement, a training or public service project, a contract, or other sponsored mechanism. Responsibilities include the intellectual conduct of the project, fiscal accountability, administration, and compliance. It is possible that the PI may share these responsibilities with a multi-investigator team.

Project Director (PD) identifies an individual responsible for the conduct of a non-research sponsored project. Responsibilities are the same as the Principal Investigator.

Co-Principal Investigator (Co-PI) identifies a senior member of the key personnel team who shares administrative, fiscal, and scientific conduct with the PI on research projects. The Co-PI can be named in the proposal and on project documentation as a co-PI provided this role is accepted by the sponsor. Note: NIH, for example, allows designation of only a single PI and does not recognize Co-PI as a role. As such, the term “Co-Investigator” and “multiple PI” are not terms that are interchangeable with NIH grants (See definition of MPI).

Co-Investigator (Co-I) identifies a member of the project team who conducts the scientific portion of a research project. Co-Is can be named in the proposal provided the sponsor accepts the role.    

Multiple Principal Investigator (MPI) identifies two or more individuals who share responsibility for the conduct of the project. Investigators will use the multiple PI/PD designation when all PIs/PDs share the responsibility and authority and when the sponsor so indicates. Under the multiple principal investigators concept, the National Institute of Health (NIH) refers to multiple investigators as “PI” while the National Science Foundation (NSF) does not infer any distinction in scientific stature among multiple PIs, refers to multiple investigators as “Co-PIs”.  See NIH Multiple Principal Investigators for more sponsor specifics. For both sponsors, the first PI listed will serve as the contact PI and must be affiliated with the submitting institution.

Contact PI identifies the individuals who will be entered on the Proposal Summary Form as PI/PD. Projects with multiple principle investigators must designate a Contact PI who is responsible for communications among the project team, the sponsor, and USF.