Indiana Ratio Study Analysis

Math Notebook and Calculator

Throughout 2019 and 2020, the Tippecanoe County Assessor, Eric Grossman, conducted an analysis of real property sales data that was used or excluded from Indiana county ratio studies. The results of this study was presented during the Indiana Continuing Legal Education Forum's 20th Annual Indiana Property Tax Institute Forum. The presentation given and the data used are shared in the links below for further in-depth analysis.

Eric can reached to further discuss this research via phone (765-423-9263) or email

"Statistics are the heart of democracy."

Simeon Strunsky

Trends in Assessment: Powerpoint presentation presented during ICLEF's 20th Annual Indiana Property Tax Forum on May 27, 2020.

Ratio Data Analysis Summary: Narrative with statistics and graphs that attempts to explore factors that may contribute to the percentage of sales used by a county in its ratio study.

2013 IAAO Guide to Ratio Studies: This document outlines international practices on how to validate, govern, and report assessments via ratio study processes.

Ratio Study Data 2019: This is a compilation of ratio study data from all 92 counties. This data is analyzed and discussed in the Ratio Data Analysis Summary.

Statistics for Residential Sales: These are the test statistics discussed during the presentation for residential property. Your results may differ based on your trimming policy.

Statistics for Commercial & Industrial Sales: These are the test statistics discussed during the presentation for commercial and industrial property. Your results may differ based on your trimming policy.

LVL of AV Test Data: This multi-tab output walks you through the testing process. Feel free to run your own test! Some tips: 

  • Separate vacant land for separate analysis

  • Try testing counties or groupings indivudually as well as running state-wide tests

  • Create a statistical (or other unbiased) outlier policy that utilizes a high proportion of sales

Image by Tom Rumble