SYSE.22:0 - Use This When

Use this pattern when an engineering project keeps improving one problem statement and one proposed System while the situation around both has changed. For example, a new operating condition, affected-System consequence, supplier limit, technology, or evidence result can make the old problem–solution pair obsolete even while its backlog closes.

Begin with one observation or claim that can change the current engineering decision. Put the selected problem record beside the System option it currently constrains. State the receiving decision and the claim within it that would change—for example, an admission rule, comparison coordinate, affected-System consequence, evidence need, or choice. If none changes, keep the observation without reopening this decision.

The first useful result contains these four parts:

1. the problem records selected for current attention and a separately retained problem archive;
2. actual Systems in current configurations and possible-future System-family specifications with their architecture, membership, and effectivity bases;
3. supported problem–option correspondences and unresolved mismatches; and
4. one replayable ChoiceResult: choose an option or tie-set, reject the current set, request one worthwhile probe, or refer the question to the decision and authority that can answer it.

An Agent makes the bounded choice under authority. Other Agents later perform any authorized experiment or implementation Work. A DecisionSubject states whose choice is represented; this is separate from the Agents who later perform Work.

Use SYSE.1, SYSE.16, and SYSE.17 first when project focus, operating environment, or affected Systems are unclear. Use SYSE.2 when one linked use-and-System concept is the immediate result, and SYSE.6 when the problem and option set are stable and only an architecture choice remains. Use C.18 when the question concerns only an archive or Front. A contested problem formulation may require a Problem Structuring and Decision Support Method; a changed Method may require Method Engineering.