Sub-I (The Sub-Investigator)

The Sub-Investigator (Sub-I) constitutes any member of the team of individuals conducting an investigation other than the Principal Investigator (PI).

If the PI of a clinical trial is not a physician, a qualified dentist or physician must be listed as a Sub-Investigator. Other Sub-Is can include board-certified physicians, fellows, residents, or non-physicians. Those listed as Sub-Is must make direct and significant contributions to the data.


The Sponsor selects qualified investigators, but it is the responsibility of the PI to ensure that the Sub-I is aware of their obligations and the requirements for complying with regulations. All Sub-Is must submit financial disclosure information to the sponsor.

Source: U.S. Department of Health and Human Services, U.S. Food and Drug Administration, Office of Good Clinical Practice, Center for Drug Evaluation and Research, & Center for Biologics Evaluation and Research. (2010, May). Information Sheet Guidance for Sponsors, Clinical Investigators, and IRBs Frequently Asked Questions – Statement of Investigator (Form FDA 1572). U.S. Food and Drug Administration.