Based on 327 historical office appeals in Proviso Township (2022-2025), TaxRival's data shows a 32% win rate at the Board of Review with an average reduction of 14.4% when successful.
Check Your Property →Professional office, medical office, and multi-tenant office buildings. Proviso Township sits in the South/Southwest Suburban triad of Cook County. Our analysis of historical Board of Review appeal outcomes (2022-2025) shows that office property owners in Proviso have won reductions on 32% of filings, with an average reduction of 14.4% when the BOR grants relief.
The 95th-percentile reduction is 21% — that's our plausibility ceiling for the algorithm, calibrated specifically to office appeals in Proviso. Cases above this threshold are exceedingly rare in the historical record, so claims significantly above 21% would be flagged as outliers and reviewed before filing.
The strongest recent Board of Review reductions on office property appeals in Proviso Township, drawn from BOR decisions in tax years 2022–2024. Pre-appeal AV is the Assessor's value before filing; post-appeal AV is the BOR's final decision. These are real outcomes, not estimates.
| Tax Year | Pre-Appeal AV | Post-Appeal AV | Reduction |
|---|---|---|---|
| 2023 | $731 | $339 | −53.6% |
| 2022 | $51,744 | $28,140 | −45.6% |
| 2023 | $62,301 | $39,032 | −37.4% |
| 2023 | $62,073 | $38,936 | −37.3% |
| 2023 | $122,634 | $80,098 | −34.7% |
| 2023 | $57,723 | $38,197 | −33.8% |
| 2023 | $57,723 | $38,197 | −33.8% |
| 2023 | $66,171 | $45,000 | −32% |
| 2023 | $66,171 | $45,000 | −32% |
| 2024 | $49,238 | $33,499 | −32% |
| 2023 | $86,375 | $62,500 | −27.6% |
| 2023 | $66,442 | $48,979 | −26.3% |
Source: Cook County Assessor's open data portal (appeal_history dataset). Property identifiers are not displayed for privacy; figures are public record.
TaxRival's algorithm uses township-and-class-specific calibration, not a generic countywide average. When we evaluate your office property in Proviso, we use the 21% cap from this dataset, the 32% historical win rate as a confidence input, and class-specific comparable sales matched to your asset type.
For a deeper look at how Cook County BOR appeals perform across all townships and asset classes, see our 2024 BOR appeal success rates analysis covering all 57,960 commercial and industrial appeals filed last year.
Enter your 14-digit Cook County PIN to see whether your Proviso office property is over-assessed. Our analysis is free, and if we file an appeal, you only pay 25% of first-year savings. No reduction, no fee.