C-R21
Missing and uncertain values — Reference record
Not observed, not recorded and uncertain are different states. They should remain distinguishable from a numeric zero.
| Reference record | Working notes |
|---|---|
| Overview | Missing and uncertain values |
| Practical example | Use separate status fields for missing context and uncertain attribute interpretation. |
| Limits and interpretation | A blank cell must not silently become a zero in a later chart. |
| Document control | Reference edition 2026.11 |
Measurements and examples are descriptive, not acceptance criteria.