In Cook County, the Assessor’s office oversees more than 1.3 million residential parcels, divided into three assessment districts. One of those districts is re-assessed every year using a computer-assisted mass appraisal method.
How Mass Appraisal Works
Computer-assisted mass appraisal works through a computerized sales model that considers different value components, including:
- Sales of comparable properties
- Building square footage
- Construction type
Three to five years of prior sales information is used.
To ensure uniformity between properties, only properties located in the same neighborhood are compared to each other. In addition, teardown properties—those bought for the land with the original structure demolished and replaced—are removed from the sales comparison model.
These teardowns will be valued using the new building’s characteristics, etc.
The county coordinates the gathering of this information through Geographic Information Systems (GIS), which aims to optimize Cook County’s geospatial investment in information technology. The GIS administers and coordinates land-based information across all Cook County agencies, using geography accurately developed from a photogrammetric base.
However, as Todd Ricketts, Cubs co-owner, recently found out, occasionally the assessor’s office sends out field agents to do site checks to make sure the buildings that are recorded to be on the property are in fact the buildings on the property.
People Should Always Double-Check Tax Bill Information
That is not to say that the information on a property tax assessment is always correct. Sometimes, there are mistakes, such as the wrong Property Identification Number, the incorrect square footage of the property, the incorrect number of rooms or the condition of the property. Property owners should always double-check the information sent with the property tax assessment because any incorrect information can be grounds to appeal the amount of property taxes currently owed.
Another reason many property owners appeal property taxes is a lack of uniformity, meaning the property is taxed more than similar properties in the area. On the Cook County Assessor’s website, they provide a list of properties they think are comparable, and it allows you to check them off. Property owners need to make sure that the comparable properties are similar, especially in terms of the following:
- Square footage
- Lot size
- Construction type
- Bedroom and bathroom count
Homeowners should also ensure they are receiving the tax exemptions for which they are eligible