A nearby home is a candidate, not automatically a comparable
The Assessor’s comparable-property guidance points to CookViewer and explains how to examine nearby properties and their characteristics. Start with homes that share the subject property’s relevant features, rather than selecting only neighbors with lower assessments. Record why each candidate belongs in the comparison and why obvious mismatches were excluded.
Keep the comparison consistent
Open the subject property and verify its PIN, assessment year, class, building size, construction year and neighborhood code. Use the same year and assessment stage across the comparison. A different size, use or building form can explain a difference that looks unusual on a map.
Separate recorded assessment comparisons from sale-price comparisons. For a sale, inspect the date, deed context and whether the consideration covers multiple PINs. A nominal or related-party transfer is not interchangeable with an ordinary market sale. Missing condition or renovation information should be recorded as a limitation, not assumed equal.
Turn a screening result into evidence
A Cook County Records peer gap is a reproducible screening calculation, not an appeal decision. Save the candidate PINs, original values, source dates and selection reasons. Verify each candidate in the official records before filing and use the reviewing office’s current evidence requirements.
For example, the Park Ridge street directory lets you open each address on a street and inspect its underlying history. A coherent set of similar properties is more informative than a single unusually low assessment. If no defensible set exists, retain that limitation rather than widening the comparison until a desired result appears.
Sources: Official Assessor appeal rules