US Clinical Trial Investigator & Site Intelligence Graph (unique-NPI, historical)

A historical Clinical Trial Investigator & Site Intelligence Graph connecting unique-NPI investigators, specialties, organizations, facilities, trials, sponsors, conditions, interventions, phases, study status, sites, locations, and industry companies. This is not a ClinicalTrials.gov dump and not a site directory. An official becomes an investigator only when the normalized given name and family name match exactly one individual NPPES record. Ambiguous names stay out. That unique NPI is the join key to specialty, group practice, named hospital, trial title, sponsor, condition, intervention, phase, status, named site, location, and the same NPI on the provider–industry graph. `HAS_INVESTIGATOR` is the trial–investigator edge. `HAS_INVESTIGATOR_IN_YEAR` keeps the study start year so the graph is historical. Sites carry the site name and location. Hospitals carry CMS hospital names and a CCN. The delivered file is a graph: nodes, edges, and properties, with Cypher for Neo4j and Memgraph. Licensed buyers also get a keyed API stream. The ZIP remains the full historical dump. No patient-level data. No name-only investigator identity. No invented referral edges.