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    Appraisal Process

    Extraordinary Assumption

    An assumption that is directly related to a specific assignment and, if found to be false, could alter the appraiser's opinions or conclusions. It presumes uncertain information to be factual for the purpose of the analysis.

    Extraordinary assumptions are used when the appraiser cannot verify something but needs to proceed with the analysis. Common examples: assuming a property is free of environmental contamination without testing, assuming proposed construction will be completed as planned, or assuming a zoning change will be approved. The appraiser must clearly state the extraordinary assumption and note that the value conclusion is contingent upon it being true. If the assumption is later found to be false, the appraisal is invalidated. USPAP requires that extraordinary assumptions be reasonable for the assignment.

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