Whats the difference between an extraordinary assumption and a hypothetical condition? (Any sangs or jingles to help remember?) Dictionary of Real Estate Appraisal 5th Edition Extraordinary Assumption: An assumption, directly related to a specific assignment, which, if found to be false, could alter the appraiser's opinions or conclusions. Extraordinary assumptions presume as fact otherwise uncertain information about physical, legal or economic characterisitcs of the subject property; or about conditions external to the property such as market conditions or trends; or about the integrity of data used in analysis (USPAP 2010-2011 ed.) Hypothethical Condition: That which is contrary to what exists but is supposed for the purpose of the analysis. Hypothetical conditions assume condition contrary to known facts about physical, legal or economic characteristics of the subject property; or about conditions external to the property, such as market conditions or trends; or about the integrity of data used in analysis (USPAD 2010-2011 ed.) This has been something that I have seen vary from appraiser to appraiser and just trying to find a consensus. 1) An appraisal is for a prospective value of a proposed building, is the proposed building a EA or HC? 2) THe proposed building is never constructed by the prospective date? Would this apply to EA, HC or both? 3) The site of the proposed building will be constructed on a landfill and unsure of if any contamination exists? EA or HC? All opinions, stories and suggestions greatly appreciated! Thank you!