C51 · Reference edition 2026.11
Missing and uncertain values — Definition and boundaries
Not observed, not recorded and uncertain are different states. They should remain distinguishable from a numeric zero.
Scope and purpose
Start by separating the named concept from adjacent concepts. Use the observation below to identify the question the record is intended to answer. Read the caution before applying the example. A definition is useful only when another reader can tell what falls outside it.
Working notes
This atlas connects descriptive vocabulary, observation context and reference-sheet design. All example records are synthetic and exist to explain a method of documentation; they do not represent tested batches, product ratings or scientific results. The diagrams are original editorial graphics. Descriptions of perceived character are kept separate from ingredient, origin, health and certification claims. Read definitions and scale anchors before comparing records.
Practical example
Use separate status fields for missing context and uncertain attribute interpretation.
| Reference record | Interpretation |
|---|---|
| C51 | Missing and uncertain values |
| Scope and purpose | Not observed, not recorded and uncertain are different states. They should remain distinguishable from a numeric zero. |
| Limits and interpretation | A blank cell must not silently become a zero in a later chart. |
Review checklist
Write a one-sentence scope statement; identify a neighbouring concept; record what the example does not establish.