• REEYtterbium: per-element production deferred - Per-element REE production figures are deferred per ADR 002 (methodology call). Chapter-aggregate coverage is available under the `rare_earths` rollup commodity (1151 supply records).
• group-levelYtterbium: reserves reported only at the rare-earth group level - USGS Mineral Commodity Summaries publishes rare-earth reserves by country only as a single rare-earth-oxide (REO) total, never split per element. The empty reserves table reflects that reporting grain; the aggregate REO reserves are available on the `rare_earths` rollup commodity.
• no dataNo demand data - No consumption / intensity / projection rows in scope. Forward-looking demand requires either USGS MCS apparent-consumption coverage (commodity-specific) or hand-curated intensity proxies + IEA CMO scenarios.
• no dataNo commodity-decomposed recycling data - No USGS MCS Fig13 scrap rows. EU WEEE / battery EOL flows (Phase 6.1.1) are country-keyed only - see country profiles.
• datedMaterial-flow analysis is historical - All 19 material-flow records date to 2007 or earlier (Yale STAF era). They describe the anthropogenic cycle of that period, not today's system.
• datedEnvironmental footprint is dated - Cradle-to-gate intensity rows carry a 2008 inventory vintage (Nuss & Eckelman-era LCA). Current-process footprints are not yet in scope.

The eight-stage lens, the observed-vs-estimated membrane, stage-honest supply, per-stage concentration, ownership resolution and the demand lens - the full method is illustrated live on copper, nickel and lithium.

Read the methodology, illustrated live →