01
Source hierarchy
Prefer primary authoritative records. Use secondary sources for discovery or corroboration and record conflicts instead of silently choosing a convenient value.
02
Calculations
Record metric definitions, inputs, versions, units, time and geographic basis, formulas, rounding, missing-value rules, transformations, outputs, tests, and reviewers.
03
Comparisons
Confirm common definitions, units, periods, population, geography, accounting basis, revisions, and external context before comparing administrations or time periods.
04
Corrections
Published versions are immutable. Corrections create a new version, preserve the prior record, explain the change, and propagate to each language presentation.