4.4.2.4. Transactions Requiring Extraordinary Care.Not all property transactions can be used as potential comparable sales in valuations for federal acquisitions. While few types of Uniform Appraisal Standards for Federal Land Acquisitions / Legal Foundations For Appraisal Standards 

transactions are categorically excluded from consideration under modern jurisprudence,460 as a matter of law several types of sales can be considered only under certain circumstances or for limited purposes. Accordingly, careful verification and analysis of each sale is required to ensure the appraiser’s opinion of value does not reflect any legally improper considerations.461 Of course, extraordinary verification alone would not allow an appraiser to rely on a sale that cannot be considered for other reasons, such as a sale involving a different property interest than the property under appraisal,462 or a sale excluded from consideration under a legal instruction applying the scope of the project rule.463 123