By Harsha N Hegde
Cook County homeowners often assume that professional representation must produce better results. The actual data tells a more complicated story.
The type of representation depends on the appeal stage. The Cook County Assessor allows attorneys and other authorized tax representatives to file for taxpayers. At the Board of Review, anyone representing a taxpayer must be a licensed attorney. This article therefore compares DIY appeals with agent-represented appeals at the Assessor and attorney-represented appeals at the Board of Review.
From 2021 through 2025, homeowners filing on their own had slightly higher success rates than represented homeowners at the Cook County Assessor. At the Board of Review, the DIY advantage was much larger and appeared in every year from 2020 through 2025. Represented appeals, however, generally obtained larger median assessed-value reductions when they succeeded.
Those are gross assessed-value reductions, not the homeowner’s net savings. They do not account for contingency fees, which commonly take 30-50% of the resulting tax savings. A larger reduction therefore does not necessarily mean the homeowner keeps more.
In short:
- Professionally represented filers submitted far more appeals.
- DIY homeowners had higher success rates.
- Represented appeals generally obtained larger median reductions when successful, before fees.
- The DIY advantage was modest at the Assessor but substantial at the Board of Review.
Assessor appeal outcomes
The Assessor data includes only appeals recorded as closed. DIY homeowners had a higher success rate in every year, but the difference was usually small. In 2025, the success rates were nearly identical: 17% for both groups after rounding.
| Tax Year | SFR | DIY | Agent/Representative | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Closed Appeals | Reductions | Success Rate | Median AV Reduction | Closed Appeals | Reductions | Success Rate | Median AV Reduction | Closed Appeals | % | ||
| 2021 | 925,522 | 36,743 | 8,102 | 22% | $ 3,000 | 66,442 | 13,217 | 20% | $ 4,575 | 103,185 | 11% |
| 2022 | 926,001 | 43,925 | 11,418 | 26% | $ 3,028 | 79,350 | 18,409 | 23% | $ 4,749 | 123,275 | 13% |
| 2023 | 926,663 | 50,453 | 11,222 | 22% | $ 2,641 | 77,887 | 14,298 | 18% | $ 3,642 | 128,340 | 14% |
| 2024 | 928,242 | 56,988 | 11,684 | 21% | $ 2,142 | 84,121 | 14,524 | 17% | $ 3,291 | 141,109 | 15% |
| 2025 | 928,823 | 40,735 | 7,080 | 17% | $ 2,740 | 73,024 | 12,334 | 17% | $ 4,776 | 113,759 | 12% |
Note: The 2025 figures include only appeals recorded as closed in the Cook County Assessor’s data. These figures may change as appeal cases are completed and Cook County refreshes the source data.
The Cook County data catalog notes that 2020 Assessor appeals data is not fully available, so 2020 is excluded from this part of the analysis.
What the Assessor numbers show
DIY success rates ranged from 17% to 26%, compared with 17% to 23% for agent-represented appeals. Homeowners did better each year, but not by a dramatic margin.
Agent-represented appeals obtained larger median reductions every year. The gap was particularly large in 2025, when the median represented reduction was $4,776 compared with $2,740 for DIY homeowners.
That comparison is before representative fees. A 30-50% contingency fee reduces the homeowner’s net tax savings, so the larger median reduction does not by itself establish a better financial outcome.
The defensible conclusion is not that DIY homeowners crushed tax representatives at the Assessor. It is that professional representation did not improve the observed probability of obtaining a reduction, even though successful represented appeals tended to produce larger reductions.
Board of Review appeal outcomes
The difference is clearer at the Board of Review. DIY homeowners achieved higher success rates in every year from 2020 through 2025, generally by 11 to 17 percentage points.
| Tax Year | SFR | DIY | Attorney | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Appeals | Reductions | Success Rate | Median AV Reduction | Appeals | Reductions | Success Rate | Median AV Reduction | Appeals | % | ||
| 2020 | 924,893 | 42,396 | 21,355 | 50% | $ 1,857 | 116,378 | 44,391 | 38% | $ 2,170 | 158,774 | 17% |
| 2021 | 925,522 | 33,822 | 16,753 | 50% | $ 1,889 | 72,962 | 27,373 | 38% | $ 2,550 | 106,784 | 12% |
| 2022 | 926,001 | 48,084 | 25,475 | 53% | $ 2,184 | 128,192 | 55,210 | 43% | $ 3,071 | 176,276 | 19% |
| 2023 | 926,663 | 54,531 | 33,341 | 61% | $ 2,336 | 127,329 | 55,609 | 44% | $ 2,599 | 181,860 | 20% |
| 2024 | 928,242 | 57,896 | 32,644 | 56% | $ 2,156 | 129,127 | 55,424 | 43% | $ 2,617 | 187,023 | 20% |
| 2025 | 928,823 | 68,389 | 41,360 | 60% | $ 2,342 | 151,464 | 73,187 | 48% | $ 3,059 | 219,853 | 24% |
What the Board of Review numbers show
DIY homeowners succeeded in approximately 50% to 61% of appeals. Attorney success rates ranged from 38% to 48%.
Attorneys again obtained larger median reductions in every year. But unlike at the Assessor, the DIY advantage in success rates was substantial and persistent.
The 2025 results illustrate the tradeoff:
- DIY homeowners had a 60% success rate and a median reduction of $2,342.
- Attorneys had a 48% success rate and a median reduction of $3,059.
An attorney-filed appeal was less likely to succeed, but the typical reduction was larger when it did succeed.
Again, these are gross reductions. After a 30-50% contingency fee on tax savings, the homeowner’s net benefit may be substantially smaller than the headline reduction suggests.
For a closer look at unsuccessful BOR appeals, including the reasons recorded for DIY and attorney-filed cases, see why Cook County Board of Review decisions get No Change.
Why success rates alone do not prove who is better
These figures describe outcomes, but they do not establish that filing DIY causes a higher success rate.
Selection likely matters. Homeowners may file on their own when they see an obvious assessment problem, while tax professionals operating at scale may appeal many marginal properties. They may also handle more complex or higher-value cases. The public data does not fully control for those differences.
That means the analysis supports three observations, not a blanket claim that one method is always superior:
- Professional representation did not produce a higher observed success rate at either appeal stage.
- DIY homeowners had a particularly strong observed success-rate advantage at the Board of Review.
- Successful represented appeals generally produced larger median reductions before fees.
Methodology
This analysis covers detached single-family residences, split-level residences, and individually owned townhomes and row houses in Cook County property classes 2-02 through 2-10, 2-34, 2-78, and 2-95. Cooperatives, condominiums, and multifamily properties are excluded.
Each property is counted once per tax year within each representation category. A small number of properties appeared in both DIY and represented categories in the same year and can therefore appear in both groups.
For Assessor appeals:
- Only closed residential appeals are included.
- DIY appeals have no
agent_code. - Represented appeals have an
agent_code; the representative may be an attorney or another authorized tax representative. - A reduction means the certified assessed value was lower than the mailed assessed value.
For Board of Review appeals:
- DIY appeals are identified as Individual/Pro Se.
- Attorney-filed appeals are identified as Attorney.
- A reduction means the Board of Review total assessed value was lower than the Assessor total assessed value and the result was recorded as a decrease.
Success rate is the number of properties receiving a reduction divided by the corresponding number of appeals. Median reduction is calculated among successful appeals, using one reduction amount per property per tax year and representation category.
Should you hire a tax representative or attorney?
The data does not show that professional representation increases your chance of winning. At the Assessor, DIY homeowners performed slightly better than agent-represented homeowners. At the Board of Review, they performed considerably better than attorney-represented homeowners.
Represented appeals did obtain larger median reductions when successful, but those figures do not deduct contingency fees. Because representatives commonly charge 30-50% of the tax savings, the meaningful comparison for homeowners is net savings after fees, not the gross assessed-value reduction.
If you have a well-supported case and are willing to present it, the historical data gives no reason to assume that filing on your own puts you at a disadvantage.