Glossary

Assess
To place a value on property for tax purposes.

Assessed Value
The fair market value of a property, multiplied by its assessment level for for its class.

Assessment Level
The percentage of value at which property is assessed. Assessment Levels vary by major class type. Per Cook County ordinance, a property's percentage (its Assessment Level) depends on its major class type. For residential properties like single-family homes, 10% of fair market value is assessed for taxation, and for most commercial properties, 25% of fair market value is assessed for taxation. 

Assessment Review
The review of an assessment placed on a property. The first place to appeal an assessment is at the Assessor’s Office; the second level of appeal is the Board of Review (BOR); the third avenue for appeal is the Property Tax Appeal Board; the fourth is to file an objection in Circuit Court (only if filed at BOR).

Classification
The process of dividing property into various classifications for purposes of taxing them at varying levels of assessment.

Equalization Factor
A factor determined by the Illinois Department of Revenue each year to ensure an equal assessment among all 102 counties in the state. State statute requires that the aggregate value of assessments within each county must be equalized at 33 1/3% of the estimated fair market value of real property in the county. This factor is also known as the "multiplier." 

Equalized Assessed Valuation (EAV)
The Assessed Value multiplied by the Equalization Factor. The EAV is the value multiplied by a tax rate to calculate a property's tax bill.

Exemption
Release from liability for a portion of property taxes.

Extension
The calculation of the tax rate by the County Clerk based on the local municipality’s tax levy.

Fair Market Value (FMV)
The value the Cook County Assessor places on each parcel of real estate.

Market Value
The value placed on a property for assessment purposes.

Partial Assessment
An assessed value that is less than a full assessed value, because (1) improvements were added but were not usable for the entire tax year, or (2) the taxable status of the property changed during the tax year.  New construction, building demolition, or fire occurring during the taxable year are common triggers for a partial assessment.  

Property Tax
The local tax on the value of real property, land, buildings and homes.

Tax
A mandatory payment to the government in order to fund government services.

Tax Base
The total of all Assessed Values of properties. 

Tax Incentives
Incentives include exemptions, deferrals, abatements or tax credits. Incentives were established to stimulate a specific type of new growth for certain types of properties (i.e. affordable housing) or growth in areas of economic need.

Tax Levy
The amount in real estate taxes requested by each taxing body.

Tax Rate
The tax levy divided by the total equalized assessed valuation. This figure is compiled by the Cook County Clerk and applied to the equalized assessed valuation to determine the amount paid in property taxes.

Taxing Body
Units of governments that collect taxes to fund government services (the City of Chicago, Chicago Board of Education, Chicago Park District, County of Cook, and local school districts.)