1.13. Supporting Experts Opinions and Reports.  Real estate appraisal is becoming increasingly sophisticated. Preparation of an adequately supported opinion of market value often requires the assistance of consultants with special expertise. Before issuing an appraisal assignment, agencies should attempt to identify the need for such special consultants and make arrangements for such services, either by contracting with the consultant directly or by providing for the appraiser’s retention of the consultant in the appraisal contract. If an agency retains the consultant directly, it should select the consultant in cooperation with the appraiser, who will ultimately have to rely on the consultant’s analysis and conclusions. The agency and the appraiser should jointly determine the scope of work and establish qualification criteria for any consultant retained. Regardless of whether the consultant is retained by the agency or the appraiser, selection of the consultant must be by concurrence of both the appraiser and the agency. 

If the appraiser finds that an appraisal cannot be completed without a consultant’s assistance, the appraiser should notify the agency involved immediately. The appraiser may not adopt unauthorized, unreasonable, or unsupported assumptions in making an appraisal in lieu of obtaining specialized consultant assistance. 

Types of special consultants often needed include: 

• Fixture appraisers 

• Environmental engineers and auditors

• Civil engineers 

• Cost estimators and contractors 

• Market experts 

• Feasibility and planning experts 

• Statisticians 

• Geologists/mining engineers/mineral specialists 

• Hydrologists 

• Timber cruisers/foresters/forestry engineers 

• Communications experts 

In using these opinions and reports, the appraiser cannot merely accept such consultant reports as accurate, but rather must analyze such reports and adopt them only if reasonable and adequately documented and supported. The results of secondary valuation reports (minerals, fixtures, or timber valuations) cannot simply be added to the value of the land to arrive at a value of the property as a whole without proper analysis by the appraiser. To do so would violate the unit rule and professional standards. The appraiser must consider these components of the property in light of how they contribute to the market value of the property as a whole.