Chief Investigator (CI):  This is someone who leads the whole trial. So for example, BLT: Barts and the London Health Trust could act as the  lead NHS organisation for a trial.

Principal investigator (PI):  This is someone who is leading the trial at a particular hospital.

Sponsor:  Is an individual, company, institution or organisation which takes responsibility for the initiation, management and/or financing of a clinical trial. For example, QMUL: Queen Mary University of London may provide the lead research team at the National Bowel Research Centre. As a sponsor Queen Mary would have to provide the infrastructure for the trial to get done (i.e. the people managing the study, who are QM employees, office space etc.), so they have to agree that the study can be done.

Where two or more organisations share a significant interest in a study, for example, one as employer of the chief investigator and another as the principal host institution, they may elect to act as co-sponsors or joint sponsors.