USPAP 2018-2019 Edition
© The Appraisal Foundation
STANDARD 5: MASS APPRAISAL, DEVELOPMENT
In developing a mass appraisal, an appraiser must be aware of, understand, and correctly employ
those recognized methods and techniques necessary to produce and communicate credible mass
Comment: STANDARD 5 applies to all mass appraisals of real or personal property
regardless of the purpose or use of such appraisals.
STANDARD 5 is directed toward the substantive
aspects of developing credible analyses, opinions, and conclusions in the mass appraisal of properties
reporting and jurisdictional exceptions applicable to public mass appraisals prepared for ad valorem taxation
do not apply to mass appraisals prepared for other purposes.
A mass appraisal includes:
1) identifying properties to be appraised;
2) defining market area of consistent behavior that applies to properties;
3) identifying characteristics (supply and demand) that affect the creation of value in that market area;
4) developing a model structure that reflects the relationship among the characteristics affecting value in
the market area;
5) calibrating the model structure to determine the contribution of the individual characteristics affecting value;
6) applying the conclusions reflected in the model to the characteristics of the property(ies) being
7) reviewing the mass appraisal results.
The JURISDICTIONAL EXCEPTION RULE may apply to several sections of STANDARD 5 because ad valorem
tax administration is subject to various state, county, and municipal laws.
STANDARDS RULE 5-1
In developing a mass appraisal, an appraiser must:
(a) be aware of, understand, and correctly employ those recognized methods and techniques necessary to
produce a credible mass appraisal;
Comment: Mass appraisal provides for a systematic approach and uniform application of appraisal
methods and techniques to obtain estimates of value that allow for statistical review and analysis of results.
This requirement recognizes that the principle of change continues to affect the manner in which appraisers
perform mass appraisals. Changes and developments in the real property and personal property fields have
a substantial impact on the appraisal profession.
To keep abreast of these changes and developments, the appraisal profession is constantly reviewing
and revising appraisal methods and techniques and devising new methods and techniques to meet
new circumstances. For this reason it is not sufficient for appraisers to simply maintain the skills and the
knowledge they possess when they become appraisers. Each appraiser must continuously improve his or her
skills to remain proficient in mass appraisal.
(b) not commit a substantial error of omission or commission that significantly affects a mass appraisal; and
Comment: An appraiser must use sufficient care to avoid errors that would significantly affect his or her
opinions and conclusions. Diligence is required to identify and analyze the factors, conditions, data, and other
information that would have a significant effect on the credibility of the assignment results.
53 See Advisory Opinion 32,
Ad Valorem Property Tax Appraisal and Mass Appraisal Assignments