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Volume 22, Issue 2 (2025)Read More

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Articles
9 September 2025

Comparing and contrasting property tax oversight systems - Idaho and The Netherlands

Alan Dornfest, Marco Kuijper
Property tax system administration may occur at national, sub-national, or local levels and includes identification and valuation of taxable property, establishing tax rates, and billing and collection of taxes. Regardless of the initial assignment of responsibilities for these functions, both internal and external oversight are crucial to: • Providing accountability; • Maintaining public trust; • Ensuring compliance with laws; • Producing a transparent property tax system. Although much of this can be accomplished by internal quality control mechanisms, the existence of an oversight body operating independently from the valuation agency or those responsible for the tax components enables such independent corroboration of adherence to laws and good principles and practices. This type of multi-layered system exists in many places and this paper presents two such models – one in the State of Idaho in the United States and the other in The Netherlands - including the evolution of each system and how each system relates to guidance provided by the International Association of Assessing Officers (IAAO).
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Current Articles

Articles9 September 2025

State and provincial property tax policies and administration (PTPA): 2023 findings and report

Alan Dornfest, Melissa Baer, Cal Kent, Brian Guerin, Marco Kuijper, Michael Safarty, Nicole Jardine
Since 1990, IAAO has published comprehensive surveys of property tax systems in the U.S. and Canada. The 2023 update is different in many ways to the prior surveys in that it included participants from outside North America and is the longest, most comprehensive survey in the series. There is an abundance of information on property tax systems available due to the work by groups such as the Lincoln Institute of Land Policy, which conducts their own comprehensive studies, but this survey attempts to capture some additional nuance, and we rely on the depth of expertise from our volunteer members to guide us. Because of the existence of multiple surveys across time, we are able to show how these policies and administration have evolved over time and are now able to contrast North American policy against a varied international dataset we hope to broaden in the future.
Articles9 September 2025

Reconceptualizing virtual assets as taxable property: Legal and administrative implications for Vietnam

Hoang Thanh
The question of whether virtual assets should be integrated into property tax systems, and how such integration should occur, is not solely a technical matter. Rather, it implicates foundational issues relating to legal ontology, economic classification, and institutional feasibility. Property taxation has traditionally relied on the physicality, permanence, and visibility of taxable subjects (Bird & Slack, 2004). In contrast, virtual assets are decentralized, volatile, and pseudonymous. These characteristics pose significant challenges not only to legal classification but also to the mechanisms of assessment, valuation, and enforcement. Their dematerialized and borderless nature renders conventional property taxation methods inadequate, thereby necessitating a re-evaluation of existing legal doctrines and the development of technologically adaptive regulatory instruments.
Articles9 September 2025

Comparing and contrasting property tax oversight systems - Idaho and The Netherlands

Alan Dornfest, Marco Kuijper
Property tax system administration may occur at national, sub-national, or local levels and includes identification and valuation of taxable property, establishing tax rates, and billing and collection of taxes. Regardless of the initial assignment of responsibilities for these functions, both internal and external oversight are crucial to: • Providing accountability; • Maintaining public trust; • Ensuring compliance with laws; • Producing a transparent property tax system. Although much of this can be accomplished by internal quality control mechanisms, the existence of an oversight body operating independently from the valuation agency or those responsible for the tax components enables such independent corroboration of adherence to laws and good principles and practices. This type of multi-layered system exists in many places and this paper presents two such models – one in the State of Idaho in the United States and the other in The Netherlands - including the evolution of each system and how each system relates to guidance provided by the International Association of Assessing Officers (IAAO).

Most Popular Articles

Articles
1 June 2019

State and Provincial property tax policies and administrative practices (PTAPP): 2017 findings and report

Alan Dornfest, Jennifer Rearich, T. Brydon, Richard Almy
In response to a need for current information about property tax systems, since 1990 IAAO has conducted surveys of the features of property tax systems in Canada and the United States and published the results. Although the main audience comprises property tax administrators and policy makers in the two countries, readers from other countries may find the results helpful as well. The compilations of survey results published in 1990, 1991, 1992, 2000, 2009, and 2012 were based on a questionnaire sent to each Canadian province and territory and to each U.S. state and the District of Columbia. Similar to the 2012 survey the 2017 survey was limited in scope, representing an update of information and additional exploration of emerging topics. The most important focus of the 2017 survey was state appeals processes and reassessment practices.
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Articles
1 June 2018

Commercial big-box retail: a guide to market-based valuation

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This IAAO position paper provides guidance for the valuation of big-box retail properties. Over the last several years, issues involving these properties and theories about how to value them, such as the dark store theory, have resulted in great debate within both the appraisal and legal communities. Even though this paper concentrates on arriving at the market value of the fee simple interest of these properties, it provides guidance regardless of the specific law of a jurisdiction.
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Articles
1 June 2017

Understanding intangible assets and real estate: a guide for real property valuation professionals

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This guide is intended to assist assessors in understanding and addressing intangible assets in property tax valuation and does not represent a policy position of IAAO. Laws can vary from state to state, but for the majority of jurisdictions, intangible assets are not taxable, at least not as part of the real estate assessment. As a result, assessors must ensure their real estate assessments are free of any intangible value. To help determine whether something is an intangible asset, a four-part test can be applied. This guide highlights many property types that potentially include intangible assets, such as hotels, senior care facilities, and properties with valuable trade names and franchises.
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Articles
31 December 2020

A Gini measure for vertical equity in property assessments

Carmela Quintos
This paper aims to show how the Gini-based measures for inequality, commonly used in the socioeconomic literature, can be applied to property assessments. The index for vertical equity is the ratio of the Gini-based coefficient of assessment to the Gini coefficient of price. It is interpreted as the elasticity of shares of assessments to shares of prices when prices are ordered from the lowest to highest price levels. A second index is based on the difference, rather than the ratio, of the Gini-based coefficients. An important distinction between both indexes and the price-related differential (PRD) and currently used measures is that Gini-based analyses do not use sales ratios (assessment/price ratios), which are basically the behavior of the appraisal errors. Instead, they are based on measures that capture the cumulative distributional behavior of assessments relative to the cumulative distributional behavior of prices across ordered price levels. Both indexes are summary measures that are simple to calculate without regression, although there are regression-equivalent formulations that are used to statistically test for vertical equity. Because Gini-based measurements of inequality have a long history in economics, their introduction to property assessment aligns the measurement and interpretation of vertical equity with its application in other fields.
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Articles
1 December 2017

Accounting for locational, temporal, and physical similarity of residential sales in mass appraisal modeling: the development and application of geographically, temporally, and characteristically weighted regression

Paul Bidanset, Michael McCord, John Lombard, Peadar Davis, William McCluskey
Geographically weighted regression (GWR) has been recognized in the assessment community as a viable automated valuation model (AVM) to help overcome, at least in part, modeling hurdles associated with location, such as spatial heterogeneity and spatial autocorrelation of error terms. Although previous researchers have adjusted the GWR weights matrix to also weight by time of sale or by structural similarity of properties in AVMs, the research described in this paper is the first that has done so by all three dimensions (i.e., location, structural similarity, and time of sale) simultaneously. Using 24 years of single-family residential sales in Fairfax, Virginia, we created a new locally weighted regression (LWR) AVM called geographically, temporally, and characteristically weighted regression (GTCWR) and compared it with GWR-based models with fewer weighting dimensions.
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