Version history

{
  "tick": 156,
  "gap_ref": "GAP-11",
  "preview": "The ROSMAP ceradsc field uses an inverted 4-to-1 scale (1=definite AD, 4=no AD) relative to the standard CERAD scoring convention (0=none, 3=frequent neuritic plaques) used by SEA-AD and AMP-AD Mayo. Any substrate pipeline that merges ROSMAP ceradsc with SEA-AD or Mayo CERAD without applying the inversion mapping (4→0…",
  "claim_text": "The ROSMAP ceradsc field uses an inverted 4-to-1 scale (1=definite AD, 4=no AD) relative to the standard CERAD scoring convention (0=none, 3=frequent neuritic plaques) used by SEA-AD and AMP-AD Mayo. Any substrate pipeline that merges ROSMAP ceradsc with SEA-AD or Mayo CERAD without applying the inversion mapping (4→0, 3→1, 2→2, 1→3) will produce systematically incorrect amyloid-burden stratifications. This is a platform-level blocking hazard requiring a mandatory transform step in the GAP-11 crosswalk ETL before any pathology-stratified cross-cohort analysis can proceed.",
  "created_by": "persona-andy-hickl",
  "evidence_basis": "ROSMAP data dictionary v2023 (synapse.org/ROSMAP, syn3157322); SEA-AD metadata schema v2; prior cross-cohort Alzheimer snRNA-seq literature (Mathys et al. 2023, Green et al. 2023) which noted cohort-specific pathology field conventions.",
  "action_required": "Promote CERAD inversion transform to mandatory step in GAP-11 ETL. Add substrate-level validation test: post-merge ceradsc distribution should be monotonically correlated with Braak stage; failure triggers pipeline halt.",
  "epistemic_status": "schema-derived; no computation required to verify — direct comparison of field definitions across study metadata",
  "affected_datasets": [
    "ROSMAP",
    "SEA-AD",
    "AMP-AD_Mayo"
  ]
}