Custody and lineage answer different questions. A complete material history needs both, but neither should be used as shorthand for the other.
Custody describes responsibility over time
A custody record can show dispatch, delivery, receipt and acceptance between organisations or facilities. It should make discrepancies and acceptance conditions visible. It does not, on its own, explain how an upstream concentrate became a later refined product.
Lineage describes physical relationships
A lineage record connects lots through splits, blends and transformations. It identifies recorded input-output relationships, even when exact allocation is unknown. A continuous chain of lot identifiers is not a substitute for evidence that the described events occurred.
- Custody: who held or accepted the material?
- Lineage: which lots and operations are connected?
- Evidence: why should the link be believed?
Combine the views for a real question
If a customer receives a disputed quantity, custody reveals the handover and local observation; lineage shows which upstream inputs may be implicated. Keeping the views separate prevents a signed delivery note being mistaken for proof of origin or composition.
What this looks like in practice
Shipment S is accepted by a customer. Its supplier's output lot came from two documented process inputs. The acceptance establishes a custody decision for S; it does not prove which input contributed a given percentage to each delivered package.
The treatment of legal title, risk transfer and certification depends on contracts and applicable rules; this guide does not determine them.
Primary references
These sources inform the general traceability or due-diligence context. The worked example and operational recommendations above are Atlas editorial guidance.