What Does PI Stand for in Research? Simply Explained

You stumbled over the abbreviation PI? And now you are asking yourself what does PI stand for in research?

The answer is:

PI stands for Principle Investigator

Of course, PI can also stand for the mathematical constant π and many other things. However, this article focusses on the meaning and responsibilities of the principle investigator (PI) of a scientific reserach study, trial or grant.

What Is the Principle Investigator (PI) in Research?

The PI, or principle investigator, is the leading researcher of a specific study or research grant.

She or he is the person responsible for several aspects of a study, research topic or grant. Different studies may have different PIs (principle investigators). However, one person can be the PI of more than one study.

photo of woman pi principle investigator in research

What Are the Responsibilities of the Principle Investigator (PI) in Research?

The PI has several responsibilities including:

  • The planning and preparation of a research project
  • Funding acquision
  • Project administration
  • Management of cooperations and the distribution of work
  • Compliance with ethical and legal principles
  • Adherence to scientific and data protection principles
  • Compliance with contracts and sponsor agreements
  • Good scientific practice adherence
  • Approving the final version of a scientific paper

The principle investigator is the main person that is held responsible, if one of the points mentioned in the list above is violated.

What Does Co-PI or Co-I Stand for in Research?

In addition to the principle investigator (PI), there may be one or more Co-PI or Co-Is especially for larger studies.

  • Co-PI means Co-principle investigator (joint/mutual PI)
  • Co-I means Co-investigator

The Co-PIs or Co-Is have similar responsibilities or assist the PI conducting the research project or administrating the grant/study.

top view photo of people near wooden table co principle investigators co pi co-pis co-i co-is

When Are Co-PIs or Co-Is Needed?

There are different scenarios, when there are more persons required to conduct a study.

A common example is the conduct of a multicenter study. This is particularly relevant for medical trials.

In such multicentric trials, there is one PI responsible for the whole study. But then, there are Co-PIs for each participating site or hospital.

Further Research Information

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