International Association of Assessing Officers (IAAO)

Overview

The International Association of Assessing Officers (IAAO) is a nonprofit, educational and research association of government assessment officials, founded in 1934 in the United States as the National Association of Assessing Officers and renamed international in 1959 to reflect growing membership outside the US; it now has more than 8,500 members worldwide.[1] IAAO develops and publishes technical standards for property valuation and assessment administration, including its Standard on Mass Appraisal of Real Property and standards for ratio studies that test assessment accuracy and uniformity across a jurisdiction.[2]

Two of those standards — the Standard on Ratio Studies (2013) and the Standard on Property Tax Policy (revised 2020) — were read in full for this wiki rather than cited only at second hand; the ratio-studies standard defines the COD/PRD/PRB accuracy metrics the wiki's assessment-quality claims rest on, while the policy standard, notably, says essentially nothing about land value or split-rate taxation as a design choice.[3]

Relevance to Georgism

Because a land value tax requires assessing land separately from buildings, IAAO's mass-appraisal standards are the professional infrastructure most often invoked to answer the objection that land value can't be assessed accurately: the association formalizes exactly the statistical and cooperative-game methods — hedonic regression, comparable-sales, ratio studies — that make routine land/building separation possible at scale.[2]

See Also

• IAAO Standards: Ratio Studies & Property Tax Policy — the two standards read in full for the wiki
• Mass Appraisal Methods — the statistical toolkit IAAO standardizes
• Objection: Land value can't be assessed accurately — the debate IAAO's standards bear on
• Lincoln Institute — allied research organization on property tax and land policy
• Land Value Tax

Sources

1. IAAO, "IAAO's Story" — iaao.org/about/iaaos-story — used for the founding year (1934), the 1959 renaming to "International," and current membership figures.
2. IAAO, "Standard on Mass Appraisal of Real Property" — PDF — used for the existence and scope of IAAO's core mass-appraisal standard.
3. IAAO, Standard on Ratio Studies (2013) and Standard on Property Tax Policy (revised 2020). wiki summary — used for the COD/PRD/PRB metrics and the finding that the policy standard does not substantively address land/site-value taxation.