Hallucination Taxonomy

Core Hallucination Types

ADD-PATH — Unsupported Pathology

Adds a pathology, device, diagnosis, or finding that is not supported by the evidence.

LOC-LAT — Location or Laterality Error

Changes the anatomical location, lung zone, or right-left orientation of a finding.

SEV-CHG — Severity Change

Incorrectly increases or decreases the severity of a finding.

NEG-FLIP — Negation Reversal

Changes a present finding to absent or an absent finding to present.

CAUSE-WRONG — Incorrect Causal Relationship

Connects a finding and impression through an unsupported causal relationship.

DDX-WRONG — Incorrect Differential Diagnosis

Introduces a differential diagnosis that is contradicted or unsupported by the evidence.

EVID-OMIT — Evidence Omission

Omits important evidence required to support a final impression.

CONTRA — Internal Contradiction

Introduces mutually inconsistent statements within the causal explanation.

Additional subtypes and labeling rules may be specified in the official annotation and submission guidelines.