How Are Properties Reassessed?
Sept. 10, 2021
The 
Cook County Assessor will reassess your property for taxing purposes every three years. Chicago is scheduled for its reassessment in 2021.
According to the Cook County Assessor’s research, property values have generally remained steady or have increased, since Chicago was reassessed in 2018. For example, the median home price for a single-family home in the 49th Ward of Roger’s Park was around $350,000 in 2018 and $440,000 in 2020. The Assessor’s 2021 estimated median home value for the 49th Ward was $360,000.
For the 2021 reassessment of the City of Chicago, the Assessor used about 504,000 home sales from the last seven years in their model. They leveraged over two dozen characteristics for each home so their model could detect all related patterns between characteristics and sale price, so that their estimated home values were more accurate. They used a variety of location characteristics like school district, proximity of a property to a road, flood risk and income of the surrounding area.
The Assessor’s computerized statistical model uses real estate market data to estimate the value of homes that haven’t sold. The goal of this computer model is to answer the question: What would the sale price of every home be if it had sold recently in an arms-length transaction?
The process includes modeling, valuation and mailing. Computer code is used to analyze data about home sales. Patterns in how characteristics affect sale prices are detected. The output is a model which can be used to predict any home’s sale price based on its characteristics and the learned patterns. Then, the model is used to predict property values. The values are reviewed by software and the Assessor’s analysts, and any necessary adjustments are made. Finally, the reassessment notices are mailed to homeowners.
If you feel that your property’s new assessed value is not accurate, you have the opportunity to appeal that new value at the Cook County Assessor, Cook County Board of Review and the Property Tax Appeal Board in Springfield.