In tax year 2024 the Cook County Board of Review issued 490,231 decisions on residential property. It cut the assessed value on 195,556 of them: 39.9%. Half of those cuts were 5.1% of assessed value or less.
Keep both numbers in mind when you read the percentage on your Censum result. The odds say how often homes like yours got a cut of any size. They do not say how big, and they are not a promise.
Quick Answer
The odds on a Censum result estimate how often appeals on homes like yours received some reduction from the Cook County Board of Review in past years. They are not the chance of saving the dollar estimate shown, and they are not a promise. Read the odds, the evidence strength and the savings range as three separate answers. For scale: the Board cut 39.9% of residential decisions in tax year 2024, and the median cut was 5.1% of assessed value.
Three numbers, three questions
The odds answer "How often did appeals like this get any cut?" Censum builds them from 15 years of Board of Review rulings across Cook County. A reduction of any size counts as a win in that history, whether it was $50 a year or $2,000.
The evidence answers "How strong is the case this year?" This is about your file: how your assessment compares with similar homes and with recent sales, and whether the county's record of your home is accurate. A home can sit in a group with good odds and still have thin evidence this year.
The savings range answers "If it works, roughly how much?" It comes from a fair-assessment value analysis and your local tax rate. It is a range because the Board decides the size of any reduction, and that size varies widely.
A "win" is usually a small cut
The 195,556 residential cuts in tax year 2024, measured as the drop from the Assessor's value to the Board's value:
- Median cut: 5.1% of assessed value.
- Under 5%: 48.9% of cuts.
- 10% or more: 14.7% of cuts. 20% or more: 2.1%.
- Condominium units (class 299): median cut 2.6%. All other residential property: median 6.9%.
What to do with this: if your odds are high but your savings range is small, believe both. You are probably in a group that wins often by a little. Decide on the dollars, not the percentage.
The odds move with the year and the township
Share of Cook County residential decisions that got a cut, by tax year:
| Tax year | Residential decisions | Cut | Share cut |
|---|---|---|---|
| 2019 | 382,266 | 142,012 | 37.2% |
| 2020 | 299,936 | 78,466 | 26.2% |
| 2021 | 432,787 | 111,445 | 25.8% |
| 2022 | 392,855 | 111,991 | 28.5% |
| 2023 | 330,844 | 112,780 | 34.1% |
| 2024 | 490,231 | 195,556 | 39.9% |
| 2025 | 447,784 | 189,516 | 42.3% |
Place matters more than the year. Over tax years 2023 through 2025, one full three-year cycle that counts each township's reassessment year once, the share ranged from 21.5% in South Chicago, one of the city's eight assessment townships, to 53.1% in Cicero. In tax year 2025 alone it ran from 12.5% in North Chicago, also a city township, to 69.0% in Hanover.
What to do with this: do not decide on county-wide rates, including the ones here. Use odds built from homes like yours in your area.
Who filed matters too
In tax year 2024, residential appeals filed by owners themselves got a cut 54.9% of the time (37,298 of 67,981). Attorney-filed residential appeals got a cut 37.5% of the time (158,255 of 422,245). Leaving out condominium units, the split was 56.2% and 43.7%.
Over a longer stretch the pattern holds. Across the 15 tax years from 2011 through 2025, owners who filed their own appeals on houses and townhouses got a cut 63.5% of the time (457,462 of 720,240). That long-run figure is the one shown on Censum's methodology page.
That does not prove filing yourself works better. Owners who file alone may be the ones with clearer cases. It does show the Board regularly cuts appeals that homeowners file themselves, which the Board allows.
What goes into the odds
Censum's methodology page lists six signals it weighs:
- Comparable sales
- Price per square foot against similar homes
- The ratio between recent sale prices and assessed values
- Your home's assessment history
- Prior appeal outcomes on the property
- Results in your neighborhood
These map onto the two arguments the Board recognizes. One is that the value is too high for what the home would sell for. The other is that your home is assessed at a higher level than comparable homes, even if the value looks right. Our guide to overvaluation versus lack of uniformity explains both.
Why "calibrated" matters more than "high"
A model that says 90% and is right 60% of the time is worse than one that says 55% and is right 55% of the time. Calibration means the stated odds are checked against what actually happened to groups of similar appeals.
Calibration describes groups, not you. If 100 homes each show 70%, roughly 70 of them would be expected to get a cut and 30 would not. Your home is one of the 100. The number tells you which group you are in, not which side of the line you land on.
What the odds cannot see
Public records are the starting point, and they have blind spots. The odds do not know about:
- Water damage, a failing roof, or an outdated kitchen the county never recorded
- A recent purchase that was not arm's-length, such as a sale between relatives
- Errors on your property record card that you have not checked yet
- Whether you file on time, with the evidence, in the right venue
The last one matters most. A strong file submitted after the window closes has no odds at all. Every township has its own window. The last file date is printed on your notice, and the Board lists its closing dates by township.
How to use the three numbers together
These are rules of thumb, not advice for your case.
Good odds, solid evidence, meaningful savings. The clearest case for filing. Gather the documents and file inside the window.
Good odds, weak evidence. Strengthen the file first. A closing statement, dated photos of condition problems, or a corrected square footage can change the case.
Low odds, large savings. Filing can still be rational. Know what it costs before you start, and do not pay a large share of a result that probably will not come.
Any odds, tiny savings. If the likely reduction is a few dollars a year, the time and fees may not be worth it unless you file yourself for free.
A quick way to weigh it is expected value. Suppose your odds are 60% and the estimated savings are $600 a year. On average that is worth about $360 in the first year, before fees. This is illustrative arithmetic, not an estimate for your home. Compare that number, not the headline savings, with what you would pay for help.
A reduction can last longer than a year
For an owner-occupied home, a Board of Review reduction generally stays in effect for the rest of that three-year assessment cycle, unless something substantial changes. A reduction won in a reassessment year can therefore help for up to three tax years.
The next reassessment starts from a fresh value. Your bill can still change every year because of tax rates and the state multiplier.
The numbers behind this article
Figures are Censum's tabulation of the Cook County Board of Review Appeal Decision History dataset, accessed November 7, 2026. They count PIN-level decisions, not appeals filed. Houses and townhouses are the Assessor's classes 2-02 to 2-10, 2-34, 2-78 and 2-95. Cut size is the Assessor's total assessed value minus the Board's, divided by the Assessor's. Tax year 2025 decisions appear for all 38 townships. Censum is independent and not affiliated with the Board or any county office.
Sources
- Censum methodology
- Cook County Board of Review, residential appeals
- Illinois Property Tax Code, 35 ILCS 200/16-147 (reduced assessment of homestead property)
- Cook County Assessor, assessment calendar and deadlines
- Censum tabulation of the Cook County Board of Review Appeal Decision History dataset (Cook County open data), accessed November 7, 2026; PIN-level decisions.
FAQ
Does 70% odds mean a 70% chance I save the estimate shown?
No. It means appeals on similar homes historically received some reduction about 70% of the time. The size of any reduction is a separate question, and the savings range is Censum's estimate of it.
How big is a typical Board of Review cut on a home?
In tax year 2024 the median residential cut was 5.1% of assessed value. For condo units the median was 2.6%.
Why are my odds high but my savings small?
Some homes win often but by small amounts. If your assessment is only slightly above comparable homes, the Board may cut it, but not by much. That is why the savings range sits next to the odds.
Can my odds change?
Yes. New sales, a new notice, corrected records or documents you add can all change it. Run the check again after your notice arrives.
Does Censum guarantee a reduction?
No. The Board of Review decides every appeal. Paid Censum packets include a next-year credit if you file on time and the Board grants no reduction.
Next step
Run the free check, then read the three numbers in order: odds, evidence, savings. No email or signup is needed to see your result. Check my property
Censum LLC is a data and analytics company, not a law firm and not a tax advisor. You file your own appeal. Censum is independent and is not affiliated with Cook County or any government agency.