Final answer:
An appraisal must include an effective date, the appraiser's signature, and a certification statement to be considered professional and valid, ensuring the credibility of the report and adherence to standards.
Step-by-step explanation:
When conducting an appraisal, several components are essential for it to be considered valid and professional. An appraisal typically must include an effective date, which signifies the point in time at which the appraiser's opinions and conclusions apply to the property. Additionally, the document should have the signature of the appraiser to confirm their responsibility for the information provided within the report. Finally, a certification statement is necessary; it declares that the appraiser has performed the appraisal in accordance with the applicable standards and has no undisclosed interest in the property. This certification ensures the credibility and ethical compliance of the appraisal process.