IAAO Ratio Study Practices Survey Results
Periodically over the past 20 years, prevalent practices and issues in ratio studies have been explored by comparing U.S. states, Canadian provinces and territories, and a few local jurisdictions in terms of frequency of studies, standards used to evaluate results, and final use of results. Surveys were conducted in 1989, 1992, 1994, 1997, and 2003, and the results reported by Dornfest (1993, 1995, 1997) and Dornfest and Thompson (2004). The latest surveys were conducted by the IAAO Technical Standards Committee in 2008 and 2011.
Disclaimer: Users of this data should exercise caution when interpreting totals. Some totals in the final report are different from the raw data based on interpretation and selective follow-up.
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State and Provincial Ratio Study Practices: Results of 2011 Survey (
652 KB)
(Published in Journal of Property Tax Assessment & Administration, Vol. 9, Issue 1)
State and Provincial Ratio Study Practices: 2011 Raw Data (Excel file, 150 KB)
State and Provincial Ratio Study Practices: Results of 2008 Survey ( 445 KB)
(Published in Journal of Property Tax Assessment & Administration, Vol. 6, Issue 2)
State and Provincial Ratio Study Practices: 2008 Errata (updated August 2009, 37 KB)
State and Provincial Ratio Study Practices: 2008 Raw Data (Excel file, 189 KB)
(Text responses from survey are provided in a separate file.)
State and Provincial Ratio Study Practices: 2008 Tally of Results (Excel file, 477 KB)
2008 Written Responses and Notes in Survey (Excel file, 61 KB)
IAAO 2003 Ratio Study Practices Survey ( 3 MB)
(published in Journal of Property Tax Assessment & Administration, Vol. 1, Issue 1)