By Harsha N Hegde
Berwyn Township homeowners who appealed their assessments themselves had a higher success rate than agent-represented homeowners in every year from 2021 through 2025.
Across those five years, 17.7% of DIY Assessor appeals received a reduction, compared with 14.5% of agent-filed appeals. DIY appellants filed more than twice as many appeals and obtained nearly three times as many reductions.
The difference does not prove that filing without an agent causes a better result. The two groups may involve different properties, evidence, requested values and case difficulty. It does show, however, that Berwyn homeowners are capable of obtaining meaningful reductions without professional representation.
2026 deadline update: Berwyn Township’s Cook County Assessor appeal window closed on July 6, 2026. The Cook County Board of Review is accepting Berwyn appeals through September 29, 2026. Homeowners who missed the Assessor deadline, or did not receive the reduction they sought, can still file directly with the Board of Review.
Key findings
- DIY appellants had a higher Assessor success rate in every year from 2021 through 2025.
- Over five years, DIY homeowners filed 5,607 appeals and obtained 990 reductions, a 17.7% success rate.
- Agents filed 2,370 appeals and obtained 344 reductions, a 14.5% success rate.
- The 2023 reassessment produced the highest appeal volume and success rates for both groups.
- In 2023, 31.7% of DIY appeals and 29.4% of agent-filed appeals received reductions.
- DIY homeowners received the larger median assessed-value reduction in 2023, 2024 and 2025. Agents had the larger median in 2021 and 2022.
- The Assessor results do not determine what will happen at the Board of Review, which conducts a separate review.
Berwyn Township Assessor appeal results
| Tax year | SFR | DIY appeals | Agent-filed appeals | Total | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Appeals | Reductions | Success rate | Median AV reduction | Appeals | Reductions | Success rate | Median AV reduction | Appeals | % of SFRs | ||
| 2021 | 9,893 | 825 | 58 | 7.0% | $1,420 | 399 | 13 | 3.3% | $1,906 | 1,224 | 12.4% |
| 2022 | 9,900 | 905 | 100 | 11.0% | $1,760 | 310 | 23 | 7.4% | $2,051 | 1,215 | 12.3% |
| 2023 | 9,911 | 1,566 | 496 | 31.7% | $2,215 | 761 | 224 | 29.4% | $2,178 | 2,327 | 23.5% |
| 2024 | 9,919 | 1,014 | 148 | 14.6% | $2,122 | 445 | 39 | 8.8% | $1,953 | 1,459 | 14.7% |
| 2025 | 9,929 | 1,297 | 188 | 14.5% | $1,784 | 455 | 45 | 9.9% | $1,464 | 1,752 | 17.6% |
| Total | Not combined | 5,607 | 990 | 17.7% | Not combined | 2,370 | 344 | 14.5% | Not combined | 7,977 | Not combined |
SFR means single-family residential properties included in this analysis. The final percentage shows total DIY and agent-filed appeal counts as a share of the SFR count for that tax year. Because a small number of properties may appear in both representation categories, it should not be read as an exact percentage of unique properties appealed.
What the Assessor numbers show
DIY homeowners had the higher success rate in all five years, but the size of the advantage varied. It ranged from 2.3 percentage points in the 2023 reassessment year to 5.8 points in 2024.
The 2023 results stand out. Total appeal counts equaled 23.5% of the Berwyn SFR count, and success rates rose sharply for both DIY and agent-filed cases. DIY homeowners obtained reductions in 31.7% of their appeals, while agents succeeded in 29.4%.
Appeal activity remained elevated after the reassessment. Total Assessor appeals represented 14.7% of Berwyn SFRs in 2024 and 17.6% in 2025, compared with approximately 12% in 2021 and 2022.
Median reductions do not show a consistent advantage for either group. Agents obtained larger median reductions in 2021 and 2022. DIY homeowners obtained larger median reductions in the next three years. In 2025, the median DIY assessed-value reduction was $1,784, compared with $1,464 for agent-filed appeals.
These are assessed-value reductions, not tax savings. Cook County residential property is generally assessed at 10% of market value, so a $1,784 assessed-value reduction corresponds to approximately $17,840 in estimated market value. The effect on the tax bill depends on the property’s tax rate, exemptions and other factors.
The Assessor deadline passed, but the Board of Review is open
The 2026 Assessor appeal deadline for Berwyn Township was July 6. Missing that deadline does not prevent a homeowner from filing with the Cook County Board of Review.
The BOR is a separate reviewing authority. Berwyn’s 2026 BOR filing period opened August 31 and closes Tuesday, September 29, 2026. Filing is free, and a homeowner may file without an attorney.
Homeowners who filed at the Assessor may also continue to the BOR if they received no reduction or believe the Assessor’s reduction was insufficient. They should build the BOR case around evidence supporting a lower assessed value, such as comparable assessments or recent arm’s-length sales, rather than merely stating that the assessment increased or the tax bill is too high.
CookCountyAppeal.tax analyzes your property, identifies relevant comparable homes and estimates a potential reduction. Check your potential reduction for free before the September 29 deadline.
Berwyn homeowners can file through the Cook County Board of Review appeal portal. Confirm the closing date and submission requirements on the official site before filing.
Does the data show that DIY is better than hiring an agent?
The data shows that DIY appellants had higher observed success rates. It does not establish that DIY filing caused those results.
Agents may appeal a broader range of properties, including marginal or more difficult cases. DIY homeowners may be more likely to file when they see a clear assessment problem. The public data does not control for differences in property characteristics, evidence quality, requested values or case complexity.
The practical conclusion is narrower: historical results provide no basis for assuming that a Berwyn homeowner needs an agent to present an effective Assessor appeal. A well-supported DIY case can succeed.
The median reductions in the table are also gross assessed-value reductions. They do not account for fees charged by a representative. When professional representation is priced as a percentage of tax savings, homeowners should compare their expected net savings after fees rather than looking only at the gross reduction.
How the analysis was calculated
This analysis covers single-family residential properties in Berwyn Township for tax years 2021 through 2025. Assessor data for 2020 is unavailable and was excluded rather than treated as zero appeals.
An appeal was counted as successful when the certified assessed value was lower than the mailed assessed value.
The success rate is calculated as:
Number of appeals receiving a reduction ÷ total appeals filed
DIY appeals have no identified agent_code. Agent-filed appeals have an agent_code associated with the appeal. Median reductions include only appeals that received a reduction.
The five-year success rates are weighted rates calculated from total reductions divided by total appeals. Annual median reductions were not averaged because an average of annual medians would not be a valid five-year median.
Data limitations
- These results describe historical associations, not causation.
- The analysis does not control for property characteristics, evidence strength, requested reduction, case complexity or appellant selection.
- A property may have more than one appeal record or change representation. Public records do not always allow every procedural difference to be isolated.
- A reduction in assessed value is not the same as tax savings.
- Historical Assessor outcomes do not predict how the Board of Review will decide a case.
- Cook County may refresh or correct its public datasets, so the figures can change.
Historical results cannot predict the outcome of an individual appeal. Homeowners should review their assessment, comparable properties and current filing requirements before submitting a case.