When an extraordinary assumption is used in an appraisal, the report must state the extraordinary assumption and:

The Uniform Standards of Professional Appraisal Practice (USPAP) is the generally recognized ethical and performance standards for the appraisal profession in the United States. To become a real property appraiser in the United States, appraisers must take the 15-Hour National USPAP Course (or its equivalent).  Additionally, real property appraisers must take the 7-Hour National USPAP Update Course (or its equivalent) once every two calendar years.