Each year, BNHI collects data from the National Health Insurance program and sorts it into data files, including registration files and original claim data for reimbursement. These data files are de-identified by scrambling the identification codes of both patients and medical facilities and sent to the National Health Research Institutes to form the original files of NHIRD.

The registration files include:
Registry for contracted beds (BED)
Registry for contracted specialty services (DETA)
Registry for contracted medical facilities (HOSB)
Supplementary registry for contracted medical facilities (HOSX)
Registry for board-certified specialists (DOC)
Registry for medical personnel (PER)
Registry for catastrophic illness patients (HV)
Registry for medical services (HOX)
Registry for drug prescriptions (DRUG)
Registry for beneficiaries (ID)