How does PNCC define PI or Co-PI? August 26, 2022 21:44 We follow NIH’s definitions for these terms. Here is a link to NIH’s website glossary for PI and then Co-PI. Related articles What are the proposal deadlines? How do I apply for more hours? How do I see my proposal score and review comments? Why is one person required to come on-site for a Screening Access proposal? What is required for submission?