PTAXSIM: a tool for policymakers to enact property tax reform based on data

2023 NACo Achievement Award Winner

Cook County, Ill., IL

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About the Program

Category: Community and Economic Development (Best in Category)

Year: 2023

Cook County is the largest market-based property tax assessment jurisdiction in the United States, and one of the most confusing for its 1.9m property owners. Property tax rates and assessments can change every year. The lack of transparency makes it hard for residents to predict bills and impedes data-informed policy analysis and property tax reform. Cook County Assessor Fritz Kaegi tasked the Data Team with creating code and a centralized database to analyze the impacts of assessments, levies, exemptions, and TIFs on the property tax system. The outcome is the Property Tax Simulator, or PTAXSIM: a software code package implemented in the coding language R, designed to recalculate changes to property tax bills. It uses real assessment, exemption, TIF, and levy data to generate historic, line-by-line tax bills for any property from tax years 2006 to 2021. PTAXSIM allows users to recalculate and analyze single or multiple historic tax bills simultaneously. It is an unprecedented resource for academics, journalists, and policymakers. In the 3 months since its publication, PTAXSIM has been featured in a recorded talk for civic tech enthusiasts, received public suggestions for added data, used to produce 5 counterfactual analyses, and is in use by external policy researchers.