How Do You Attach Six Comparable PINs to a Cook County Appeal?

Cook County homeowners may submit up to six comparable PINs with an online Assessor appeal based on lack of uniformity. The limit is not a target that rewards quantity by itself. Six weak comparisons can be less persuasive than a smaller, coherent set that closely matches the subject property’s class, location, size, age, and features.

The Assessor will conduct its own analysis, so owners are not required to find comparables. Submitting a carefully selected set can still help frame the problem: similar homes are assessed differently, and the differences are not explained by material property characteristics.

What makes a property comparable in Cook County?

Start with the same assessment neighborhood and property class when possible. Then compare building type, square footage, age, exterior construction, lot size, condition, number of units, and other characteristics that affect value. Proximity alone is not enough. Two homes on the same block may differ substantially in size, style, renovation, or use.

The Assessor recommends Cook Viewer because it can apply filters using neighborhood, class, square footage, and age. Use the map as a research tool, then open each candidate’s property details to check whether the database actually supports the comparison.

Should you choose only the lowest assessments?

No. The official appeal rules warn against cherry-picking lower-valued properties. A credible comparison set should reflect the market and assessment neighborhood rather than hide obvious higher assessments. If a candidate is materially different, explain the difference or leave it out.

Uniformity is not simply a list of inexpensive homes. The question is whether similar properties are assessed consistently. A useful submission shows the subject and comparables on the same basis, such as assessed value per square foot, while also noting features that could justify a difference.

How many comparables should you include?

The online process permits up to six comparable PINs. The Assessor’s current rules say an appeal based on comparables should provide at least three, and recommend at least five. That means the practical range is usually three to six, but relevance remains more important than filling every slot.

A tight group of five genuinely similar properties can tell a clearer story than six scattered properties chosen only because their assessments are low. If a sixth candidate introduces a different class, neighborhood, unit count, or construction type, it may weaken the analysis.

How do you attach the comparable PINs?

The Assessor describes two methods. One option is to print or save each comparable property’s information as a PDF and name the file with the words Comparable PIN followed by that property’s PIN. The other is to export a list of up to six comparable PINs to one Excel file and name it for the subject property’s PIN.

Upload the file or files in the online appeal’s Attachments area designated for comparable PINs. Check that every PIN is complete, every document opens, and the subject property has not been mistakenly listed as one of its own comparables. Keep a copy of the final upload package and filing confirmation.

What explanation should accompany the list?

Briefly state why the properties are comparable and what the comparison shows. For example, identify that the homes share a neighborhood code, class, construction type, approximate square footage, and age range, then explain the relevant assessment difference. Avoid conclusory statements that do not connect the evidence to the subject.

If the property record is wrong, address that separately. A square-footage or class error can distort the comparison. Provide evidence supporting the correction rather than forcing the subject into a group that only appears similar because the underlying data is inaccurate.

Should comparable PINs support uniformity or market value?

Comparable assessments most directly support a lack-of-uniformity argument: similar properties should be assessed consistently. Comparable sales can support an overvaluation argument when they reflect arm’s-length market transactions near the relevant valuation date. Do not combine the two theories without explaining what each table or attachment is intended to prove.

For uniformity, compare assessed values on a consistent basis and account for differences in characteristics. For market value, focus on sales timing, transaction conditions, and physical similarity. A low assessment is not automatically a valid sale comparable, and a low sale price is not automatically evidence that neighboring assessments are nonuniform.

Before uploading, create a one-page comparison table with the subject in the first column and one column for each comparable. Use the same rows for every property: PIN, class, neighborhood, building type, age, square footage, lot size, assessed value, and the metric being compared. The table does not replace the official property records, but it makes inconsistencies and weak candidates easier to spot.

Recheck the property details shortly before filing. A candidate chosen from an old spreadsheet or third-party listing may contain stale characteristics. The Assessor will review county data, so your comparison should use current official records and clearly identify any characteristic you believe is inaccurate.

Do comparable assessments guarantee a reduction?

No. The Assessor reviews its own data and may identify differences not obvious from the initial search. Comparable evidence supports a uniformity argument, but it does not guarantee a particular result. A successful change affects assessed value; the eventual bill also depends on equalization, exemptions, and tax rates.

For help evaluating a residential comparison set, review Younis Law Group’s Cook County residential property tax appeal service and confirm the current filing window on the deadline tracker before preparing attachments.

This article is general information, not legal advice. Always follow the current official filing instructions and rules for the agency reviewing the appeal.