What is the Role of a Principal Investigator in a Clinical Trial?

What is a Principal Investigator?

A principal investigator (PI) is the person responsible for overseeing a clinical trial, research grant, or other sponsored research project. In clinical trials, also known as medical studies, principal investigators generally are physicians that carry out the study plan, known as the clinical trial protocol. The principal investigator also analyzes the data and reports the results of the research study.

The Roles Principal Investigators play in Clinical Trials

Depending on the clinical trial, principal investigators can be contributors or medical experts that help design the clinical trial protocol, and/or they may simply oversee a single site or clinic’s participation in the trial. Most principal investigators work at a clinical research site, and there are often many principal investigators and locations supporting any given trial.

Day to Day as a Principal Investigator

In a typical workday, a principal investigator may evaluate a potential participant’s eligibility for the clinical trial, provide medical advice or care to participants as it pertains to the study, and ensure that all the documentation for a trial has been recorded properly and accurately. Principal Investigators also assess and report any potential adverse events that could have been caused by the investigational product being studied.

Principal investigators can oversee several clinical trials simultaneously, depending on the size and labor intensity of the studies. Additionally, principal investigators may also serve as practicing doctors that see patients day-to-day beyond the clinical trials they are overseeing.

Training and Qualifications of a Principal Investigator

In clinical trials, principal investigators generally are doctors, though can sometimes be nurse practitioners (NPs), as both professions demand a deep understanding of health and medicine. Principal Investigators must be knowledgeable in their fields of research, and for clinical trials focusing on a specific sub-area of medicine or disorder, principal investigators tend to be specialists like neurologists, urologists, ob-gyns, dermatologists, ophthalmologists, etc.

How Physicians Become Principal Investigators

Becoming a principal investigator for clinical trial as a practicing physician can happen in several ways. The physician may decide to conduct research themselves by learning the rules and regulations for conducting clinical trials, applying for upcoming trials, obtaining IRB approval, and enrolling participants in the awarded trials. Additionally, physicians may decide to partner with a site network like Velocity to help establish and maintain compliant operations.


Further Reading

“Multidisciplinary Approach to Protocol Writing”, Applied Clinical Trials Online:

“What is a Principal Investigator (PI) and who is eligible?”, University of Massachusetts Amherst:

“Steps to Become a Clinical Trial Investigator”, PPD:

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