Advisory Opinions are best described as:

Advisory Opinions are best described as guidance provided by the Appraisal Standards Board (ASB) to help practitioners understand and apply the Uniform Standards of Professional Appraisal Practice (USPAP). Although they provide valuable insights, Advisory Opinions are not mandatory regulations; rather, they serve to clarify or interpret USPAP provisions. This is crucial because it underscores the distinction between binding requirements and supportive guidance.

As such, while understanding Advisory Opinions is important for compliance and best practices in appraisal, the adherence to them is not enforced legally like the actual USPAP rules. Practitioners may choose to follow these opinions to enhance their work but are not obligated to do so in the same way they are required to follow USPAP standards. Therefore, describing Advisory Opinions as not part of USPAP accurately reflects their role in the framework of appraisal practice.