How to Read Your Block's Appeal Pipeline — Mailed vs. Certified vs. Board
· Updated
Cook County publishes your assessed value at three stages — mailed, certified, and board. Here's what each one means and how to read your own parcel's progression.
Correction (October 3, 2026): An earlier version of this article said the Assessor's certified value includes Certificates of Error and that any drop below the mailed value means an appeal reduced the assessment. A Certificate of Error corrects a value after the Assessor has certified it, and the Board of Review can also change an assessment on its own motion, whether or not the owner filed a complaint (Cook County Assessor; 35 ILCS 200/16-95).
Most Chicago owners see one assessment number and assume that's the number. In Cook County, there are usually three, and the differences between them tell much of the story of an appeal. Learn to read the sequence and you can see, at a glance, where assessments around you came down after the first notice.
The three stages, in plain English
- Mailed — the Assessor's first-pass value, the one that arrives in your mailbox. This is the opening number, not the final one.
- Certified — the value after the Assessor's Office closes appeals for your township (Cook County Assessor, Assessed Values dataset). If you appealed to the Assessor and got a reduction, it shows up here. A Certificate of Error is a separate step: it corrects a value after the Assessor has certified it (Cook County Assessor).
- Board — the value after the Board of Review, an independent body, issues its decision. This is the final assessed value for the year.
The stages run in order: mailed first, then certified, then board. Not every parcel reaches every stage in every year — if no one appealed, the mailed value can simply carry through.
Reading the direction
Here's the tell. When a certified or board value lands below the mailed value, the assessment was reduced at that stage. That's what a successful appeal looks like, but it isn't proof of one: the Board of Review can also change an assessment on its own motion, whether or not the owner filed a complaint (35 ILCS 200/16-95). When the numbers hold flat across stages, the mailed value stood, though a denied appeal looks flat too. To see whether an appeal was filed at all, look up the PIN on the Treasurer's Cook County Property Tax Portal or the Board of Review's Decision History. Track the values year over year and you're reading where your block's assessments came down: a street where board values routinely dip below mailed is often a street where owners are working the process — and possibly where the first-pass values are running high.
A stage word on every number
This is why "what's my assessment?" is a slightly incomplete question in Cook County. The honest answer is always "as of which stage?" A board value from two years ago and a mailed value from this year are not the same kind of number, and comparing them without the labels is how people scare themselves. Every assessed figure carries its stage.
What about the appeal window?
Appeal windows in Cook County open and close by township, on a schedule the county sets each cycle. When there is an open window on record for a parcel, Civic Worth flags it. When there isn't one on record, the report says so rather than inventing a date — because a wrong deadline is worse than no deadline. Treat the flag as a prompt to confirm with the Assessor's or Board's official calendar, not as legal advice.
See your own parcel's progression
On a Chicago parcel report, the tax section lays out the mailed → certified → board values for the years on record, so you can see your own progression and how it compares to the block around you. If you're heading into the 2027 Chicago reassessment, this is the sequence your new mailed value will enter.
Find your parcel from the Chicago hub or your community area — Logan Square, Hyde Park, Austin, or any of the 77. Every address resolves to its 14-digit PIN and its full assessment history, three stages and all.
Sources
- Cook County Assessor, Assessed Values (Cook County open data)
- Cook County Assessor, Certificates of Error for Valuations
- Cook County Assessor, Assessment & Appeal Calendar
- Cook County Board of Review, Frequently Asked Questions
- Cook County Board of Review, Decision History (search by PIN)
- Illinois Compiled Statutes, 35 ILCS 200/16-95 (Board of Review powers)
- Cook County Treasurer, Cook County Property Tax Portal FAQ
- Illinois Compiled Statutes, 35 ILCS 200/9-220 (Cook County reassessment districts)
- City of Chicago data portal, Boundaries - Community Areas
Frequently asked
What are the three stages of Cook County property assessments?
The three stages are: Mailed (the initial value the Assessor's Office estimates and mails to owners), Certified (the value after the Assessor's Office closes appeals), and Board (the value after the Board of Review closes appeals, which the Board says sets the final county valuation for that tax year) (Cook County Assessor, Assessed Values dataset; Cook County Board of Review). A Certificate of Error is separate: it corrects a value after the Assessor has certified it (Cook County Assessor).
How can I tell if a property owner appealed their assessment?
A drop shows a reduction, not necessarily an appeal. When a certified or board value lands below the mailed value, the assessment was reduced at that stage. That's what a successful appeal looks like, but the Board of Review can also change an assessment on its own motion, whether or not the owner filed a complaint (35 ILCS 200/16-95). When numbers hold flat across stages, the mailed value stood, and a denied appeal looks the same. To see whether an appeal was filed at all, look up the PIN on the Treasurer's Cook County Property Tax Portal or the Board of Review's Decision History.
Which assessment value is final in Cook County?
The board value is the final assessed value for the year. This is determined after the Board of Review, an independent body, issues its decision on the property assessment.