Portfolio Triage
Paste a book of Cook County PINs. Get back every parcel ranked by what an appeal is actually worth — the reduction the assessor's own records support, the tax it saves, and whether it covers the hours it would take. Up to 1,000 parcels a run.
Why this exists
Every property-tax platform on the market manages appeals somebody has already decided to file — deadlines, documents, approvals, status. All of them begin after a human has answered the expensive question, which is: out of these eight hundred parcels, which sixty are worth an analyst's afternoon?
Answering it needs the assessment roll, the recorded sales, and a comparable pool for every parcel in the book. That is why the tracking vendors do not answer it, and it is the part already built here.
What each parcel is tested against
| Its own recent sale | Where the parcel itself changed hands at arm's length in the last four years, that price — brought to today's market — is the strongest evidence there is. A board that will argue about comparables all afternoon has little to say to the subject's own closing statement. |
|---|---|
| Uniformity | Assessed value per square foot against the median for the same class in the same assessor neighbourhood. This is the ground most Cook appeals are actually won on, because it is provable from the assessor's own published roll. |
| Market value | Assessed value against the statutory 10% of what comparable homes actually sell for, from an IAAO sales-ratio study of recorded arm's-length sales. |
| Condominiums | Every one of Cook's 457,839 condominium PINs carries no building square footage, so both per-square-foot grounds are unavailable. They are compared instead against the other units in their own declaration — the grouping Cook itself uses to assess them. Parking stalls and storage lockers are filed in that same class at token values and are excluded, or they would drag the median to nothing. |
It has to be able to say "drop it"
A screen that flatters every parcel is worthless, and it is the predictable failure of anything paid per filing. Roughly two-thirds of a typical book comes back not worth the cost of working it, and this says so, with the arithmetic attached. The hours you do not spend are reported as a total, because that is the actual return on a screen.
The market estimate is built from homes that sold, and homes that sell are better presented than homes that do not. That pushes the estimate up and the claimed over-assessment down — so this under-finds rather than over-finds. For a tool that decides where billable time goes, that is the correct direction to be wrong in.
The numbers you control
A reduction in assessed value becomes money only through the equalizer and your composite tax rate: saving = reduction × equalizer × rate. The equalizer is published (3.0355, 2024). The composite rate is not — it runs from roughly 6.5% in parts of Chicago to over 20% in the south suburbs, so it is yours to set, and the figure used is printed with the results. Hours, hourly cost and your contingency share drive the ranking, because the same parcel is worth different things to different firms.
ParcelProof is not a law firm, does not file on your behalf, and guarantees no outcome. Every figure here is a screen to direct professional attention, not a substitute for it.