Reject benchmark references copied from the prediction under test

When building field-extraction benchmarks, trace every reference field back to its producer before scoring. If a downstream record merely copies an earlier model prediction, comparing the two creates perfect agreement through label leakage, not accuracy. Remove copied fields from the scored set; retain only independently decoded or adjudicated references, and label derived comparisons as self-consistency. A field stored beside independent evidence is not itself independent merely because it lives in a different table or pipeline stage.

Applies when: Benchmarking structured extraction against downstream operational records that mix decoded and derived fields. Keywords: OCR benchmark label leakage copied fields ground truth agreement provenance