25 CFR 700.117 - Criteria for appraisals.
(a) Appraisal standards. The Commission's appraisals shall be based upon nationally recognized appraisal standards and techniques to the extent that such principles are consistent with the concepts of value that the Commission may establish.
(b) Documentation. Appraisal reports must contain sufficient documentation, including supporting valuation data and the appraiser's analyses of that data, to demonstrate the reasonableness of the appraiser's opinion(s) of value.
(c) Conflict of interest. No appraiser shall have any interest, direct or indirect, in the habitations and/or improvements which he appraisers for the Commission that would in any way conflict with his performance of the appraisal.