Nine signals.
One score.
The Cook County Assessor values 1.8 million homes each cycle. Mistakes slip through — and the Board of Review reverses roughly 70% of the appeals that get filed. Censum re-scores every residential parcel against nine independent signals to flag the ones most likely to win at the Board. Calibrated against thousands of real BOR decisions, not modeled outcomes.
Calibration measures whether predicted probabilities match observed outcomes. A model that says "80% chance" should win 80% of the time.
The nine signals
Detects assessment increases significantly above the township median.
Compares assessment growth to actual market sale-price trajectory in the surrounding area.
Cross-references assessment increases with public building permit records.
Measures inequity in assessment-to-sale-ratio across the township.
Weights the property's historical pattern of successful or denied appeals.
Surfaces similar nearby sales assessed at materially lower ratios.
Compares against assessor-defined sister parcels for uniformity violations.
Encodes the success rate of recent BOR appeals within a 0.25-mile radius.
Filters for cases where the dollar magnitude of expected savings justifies effort.
How tiers are assigned
| Tier | Conviction score | Win probability | Price |
|---|---|---|---|
| A | ≥ 75 | ≥ 0.70 | $199 |
| B | ≥ 60 | ≥ 0.60 | $99 |
| C | ≥ 50 | ≥ 0.50 | $39 |
Built on hard data
Our analytics combine public assessment, sales, and appeal records with proprietary signal weighting and a calibrated machine learning layer trained on years of historical Board of Review outcomes.
Every input is sourced from the public record. Nothing is purchased from data brokers. We do not collect or store any personal information beyond what already exists in public assessment filings.
The specific blend of signals, weightings, training methodology, and refresh cadence is proprietary to Censum.