PSD.15:4.3 - Compare the incumbent with a serious alternative before designing a variant

Name the current offering, a plausible competing Method, and a bounded adaptation or combination only where each is live. Compare them against the same recurring result and the actual conditions, at comparable effort where possible.

Ask what each lets participants and practitioners do, what it leaves unresolved, and where it fails. In addition to analytical adequacy, consider meaningful challenge, unequal power, facilitation burden, interpretation skill, source qualification, time to a usable return and cost of maintaining the offering. State a deliberately accepted trade-off when the richer result costs more.

Do not infer that one Method is universally better because it produces a precise score, a satisfying workshop or more alternatives. A single well-qualified Method can remain the best offering for a narrow use. Plural formulations can be necessary elsewhere; a numerical comparison can still be necessary after them.

When a change is needed, state its mechanism: which reusable action, input condition, dependency, decision rule or stop changes, what remains, and why that difference could repair the failure. Distinguish this from a change in wording, display, software, local staffing or performance. The latter may require maintenance or a new fit check without identifying another Method.

For example, replacing a paper map with a digital map while preserving attribution, challenge and unresolved-claim rules may change support and access. Replacing the challenge rule with automatic aggregation of all statements changes the reusable way and can lose dissent. The same interface change can therefore have different repertoire consequences depending on what practitioners actually do.

Use current ME.15 guidance when generic variant identity, derivation or non-variant maintenance is the live subquestion and its exact claims fit. The remaining PSD question is whether that way serves the professional decision-support use: how interpretation, participation, values, uncertainty, authority and follow-up contribute to a usable return. Generic variant maintenance does not answer that field judgement.