Competency Rule, Jurisdictional Exception Rule, and Supplemental Standards
Competency Rule
Before accepting, the appraiser must determine whether the assignment can be performed competently - knowledge of the property type, the market, the analytical method, and the relevant law. If not competent, the appraiser may still accept by disclosing the deficiency to the client and taking the steps necessary to become competent (research, consultation with a specialist, additional training). Declining is permitted but not mandated; that distinction is a frequent trap. Competence is assessed at the firm level as well, and must be revisited if the assignment's scope changes mid-stream.
Jurisdictional Exception Rule
When any part of USPAP conflicts with the law, regulation, or public policy of a jurisdiction, that part is void for that assignment - but only to the extent of the conflict. Everything else still applies. The appraiser must disclose in the report which USPAP requirement was not applied and identify the legal authority creating the conflict. This is a narrow, documented exception, not a general escape hatch; it does not excuse dishonesty.
Supplemental Standards
Requirements added by a client, regulator, or program on top of USPAP. They are additional to, never a substitute for, USPAP. Disclose them when they apply and comply when they do not conflict. If a supplemental standard genuinely conflicts with USPAP, both cannot be satisfied - the conflict must be resolved, typically by declining the assignment, before anything is signed.
Rule of thumb
Competency: 'Can I do it, or can I get there and say so?' Jurisdictional exception: 'The law forbids it, and I cited the law.' Supplemental standards: 'Extra rules on top, disclosed, never instead of USPAP.'