Annex C: Performance
An informative annex on the word performance.
What annex C is
An informative annex on the word performance. The body of the document prefers functional correctness because performance is too general a term for whether a model gives the right result. The annex explains that choice and the related measures.
Annex C is informative. It explains why the document prefers functional correctness to the general word performance.
What the 2023 edition said
The first edition carried the same annex and the same preference for functional correctness over the general term performance.
What the second edition changes
The annex is kept. No change of substance is recorded in the public draft.
The FDIS text is not public. The change line above is read from the public draft, which is not the FDIS and may differ. No clause level diff is invented here. The ISO stage record is the authority for the dates.
Why it matters to the buyer
Vocabulary is a control. A contract that asks for performance can be satisfied by a fast wrong answer. A contract that asks for functional correctness has to name the task, the measure and the error rate. The annex is short, and its practical value is high: it is the argument to use when a requirement says performance without saying what result is correct.
What to write in the requirement
Replace performance with functional correctness in requirements and contracts. Where performance efficiency is also required, keep it as a separate requirement with its own measure, and state the trade-off. A supplier answer that quotes speed only has not answered the correctness requirement.
Evidence a reviewer asks for
A reviewer will look for the word performance in a requirement and ask what it means. An undefined performance target is a finding.
- Glossary decisionThe requirement set using functional correctness for the right result and performance efficiency for speed and resource use
- Trade-off recordThe accepted trade-off between correctness and performance efficiency, with the reason
- Contract checkThe contracts and statements of work read for the undefined word performance, with each replacement recorded
Where it commonly fails
- Performance is undefined
- Correctness and speed are in one requirement
- The trade-off is not recorded
What to do before publication
Split performance into correctness and performance efficiency in the requirement set.
Read across
← B Annex B (informative) Risk-based and quality-based approaches 1 Scope →
Source for annex C: ISO/IEC 25059, Annex C, retrieved 20 October 2026. The change line rests on the public draft of the second edition and ISO page 88234. The requirement, evidence and gaps are written from our record. Every source.