How many established STANDARDS are there specifically for appraisal review?

The correct answer is one because, under the Uniform Standards of Professional Appraisal Practice (USPAP), there is specifically one standard dedicated to appraisal review, which is Standard 3. This standard focuses on the process of reviewing appraisals and provides guidelines for ensuring that the appraisal review is conducted in a thorough, unbiased, and professional manner.

Standard 3 outlines the responsibilities of the reviewer, covering aspects such as the reviewer's systematic approach to evaluating the work of another appraiser, examining the data and assumptions used in the appraisal, and providing feedback that is relevant and constructive. This singular focus allows for a comprehensive understanding of the appraisal review process within the framework of USPAP.

Other options imply the existence of multiple standards for appraisal review, which does not align with the established guidelines of USPAP. Keeping in mind that there are several other standards under USPAP that pertain to different aspects of appraisal practice, the uniqueness of Standard 3 is crucial for maintaining the integrity and reliability of appraisal reviews.