METALSGOWHERE ATLAS · SUPPLY RESEARCH

Basis changes between periods

Different bases or ownership boundaries cannot be compared directly across periods.

Definitions

Term	Meaning
Basis	The structured definition of the measured material, stage or accounting measure.
Ownership boundary	Whether a value describes the whole operation or a defined ownership share.
Incomparable	A comparison for which one or more required scope fields do not match or are unknown.

If	Then
Period start, period end, basis, ownership boundary or unit differs.	Mark the records incomparable and do not calculate a change.
A required scope field is absent or a value is approximate or derived.	Do not compare the figures without an explicit reviewed comparability decision.
A note uses a familiar word for a different basis.	Use structured fields, not note keywords, to decide comparability.

The same asset name does not guarantee the same reporting boundary.
A change in a structured basis cannot be repaired by rescaling or taking a midpoint.

Records with different structured bases: The differing basis or period is shown as a scope difference, not a production change.

Cleared public fact examples
Record	Value	Unit	Data period	Basis	Ownership boundary
Kamoa-Kakula Reported actual Ivanhoe Mines	385,808	t	2025-01-01 – 2025-12-31 · FY · full year	Copper contained in mine production	100% project basis
Kamoa-Kakula Guidance Ivanhoe Mines	290,000–310,000	t	2026-01-01 – 2026-12-31 · FY · full year · revised	Copper in anode	100% project basis

Method content edition: 2026-10-07

Keep the material, period and reporting boundary explicit as you move from a country observation to a selected project.