Data quality & audit

Every public tonne and price mid carries a provenance tag. This page shows coverage, observation classes, units, and the latest automated audit.

Quality rules

• Monthly Vancouver equal-month fills are observation_class=allocated_equal_month, not VFPA monthly prints.
• No platform-provisional 2026 Vancouver months until a public monthly/YTD print exists.
• Destination Other / unlisted is residual to VFPA annual so shares sum to 100%.
• Alberta inventory-monthly prefers AER ST3; trade-press prints live in inventory-prints.json.
• Canada production quantity_mt is metric tonnes; USGS world tables ingested as Mt are converted.
• Price mid series are monthly densified from public anchors; use prices-anchors.json for non-interpolated points.
• Licensed Argus/Platts/CRU weekly assessment series are not redistributed.

Series meta

{
  "window_start": "2021-01-01",
  "window_end": "2026-07-01",
  "generated_at": "2026-07-22T20:42:26.902Z",
  "units": {
    "prices_seaborne": "USD/MT",
    "prices_tampa": "USD/LT",
    "inventory": "MT",
    "vancouver_exports": "MT solid sulphur (VFPA)",
    "canada_production": "MT (canonical); quantity_mt_millions also present",
    "us_usgs_annual": "kt sulfur content"
  },
  "export_monthly_observation_classes": {
    "allocated_equal_month": 81,
    "allocated_bridge": 12,
    "reported": 3
  },
  "inventory_observation_classes": {
    "reported": 60,
    "interpolated": 6,
    "reported_print": 1
  },
  "price_anchor_points": 101,
  "price_interpolated_points": 301
}

Audit issues

Last audit 2026-07-22T20:42:27.895Z: P0 0 · P1 0 · P2 0

Machine-readable: backfill-meta.json · audit-report.json · prices-anchors.json · exports-monthly-reported.json · /api/v1/series/meta