Associate Principal Investigator Scheme (API) In 'ROSSINI 2' ROSSINI 2 HomeDocumentsContactsAPI SchemePrivacy Statement The Associate Principal Investigator Scheme aims to develop doctors, nurses and other health professionals to become the Principal Investigators (PIs) of the future. ROSSINI 2 welcomes you to become an API. For more information on how the scheme works and to see if you can become an API, follow the link below: https://www.nihr.ac.uk/health-and-care-professionals/career-development/associate-principal-investigator-scheme.htm