Bringing Fairness and Transparency in Property Assessments

2022 NACo Achievement Award Winner

Cook County, Ill., IL

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About the Program

Category: Information Technology (Best in Category)

Year: 2022

Historically, property tax assessments across the nation have been regressive. Meaning that relative to the market, affordable homes are over assessed and higher-value homes underassessed, resulting in property tax burdens falling on lower income homeowners. To provide the best services to homeowners in Cook County – the largest market-based assessment jurisdiction in the United States – Cook County Assessor Fritz Kaegi tasked the newly created Data Science team to develop a new valuation program. The goals were to improve assessment accuracy, equity, and transparency, and reduce the need for appeals for 1.1m residential properties filed by Cook County property owners. Data Science staff created a new in-house residential valuation model using free software and open-source algorithms. The innovative model created by the Cook County Assessor’s Office (Assessor’s Office) outperforms the assessment industry standard linear models, with improvements in equity. In service of data transparency and accessibility, the Assessor’s Office creates annual and regional reports to show trends in real estate and assessments using maps, and data visualization. Reports and tools are available online and used at outreach events. Homeowners are provided numerous ways to track the local real estate market and understand the role of property assessments and taxes in local government.