Who is typically responsible to conduct research within a clinical trials group?

• A. The intergroup (IG)
• B. The clinical trials research nurse (CTRN)
• C. The institutional review board (IRB)
• D. The principal investigator (PI)

Answer: (D)

The person responsible for conducting a clinical trial at a site is the principal investigator, who has the ultimate responsibility for the study. The PI oversees the trial's conduct according to the protocol, ensures patient safety, manages informed consent, supervises data collection and reporting, and ensures regulatory and ethical compliance. They lead the research team, including any sub-investigators and study staff, and take responsibility for the integrity of the study data and adverse event handling. An intergroup network coordinates multi-site trials across institutions but does not personally conduct the research at a single site. A clinical trials research nurse handles day-to-day coordination and data collection under the PI’s oversight, rather than bearing primary responsibility for the study. The institutional review board provides ethical review and approval but does not conduct the research itself.