Assessor - Single and Multi-Family Improvement Characteristics

Cook County property characteristics for single and multi-family homes (less than 7 units) collected by the Assessor's Office from 1999 to the present. The data is improvement-level, meaning each row corresponds to an individual building on a parcel, and is used primarily for valuation and reporting. Data is updated monthly, with the current year's data becoming final after the assessment roll is certified.

Use Cases

• Predict property value using building_sqft, year_built, construction_quality, and num_bedrooms (from 30 available columns).
• Analyze renovation trends and housing stock age distribution using renovation and year_built columns.
• Classify property types and assess amenity prevalence using type_of_residence, central_air, num_fireplaces, and basement_type.
• Model tax assessment impacts by joining on pin and tax_year with other Cook County property datasets.

Strengths

• Long temporal coverage from 1999 to the present, updated monthly.
• Includes 30 detailed columns on building characteristics, amenities, and classification.
• Data is maintained by the authoritative Cook County Assessor's Office for official valuation.

Limitations

• Row count is unknown, which may limit suitability assessment.
• Data before 2021 does not include Home Improvement Exemption (HIE) characteristic updates, while data from 2021 onward does, creating an inconsistency.
• Depending on the time of year, some data may be missing for the most recent year.

Provenance

Source

Cook County Assessor's Office, published via datacatalog.cookcountyil.gov.

Collection Method

Collected and maintained by the Assessor's Office for valuation purposes.

Time Range

1999 to present

Freshness

Updated monthly. Last metadata update was 2026-04-01 15:19:42.

Geography

Cook County, Illinois, USA