In response to the 2020 COVID-19 pandemic and its anticipated effects on the residential real estate market, the Cook County Assessor will adjust residential assessments. This data can be used to replicate residential COVID adjustments. Code can be located on GitLab. See data notes for link. NOTE that the 'adjusted values' in this data will not necessarily be consistent with each individual PIN's final assessment. To get the final assessment for an individual PIN, please visit www.cookcountyassessor.com.

Neighborhoods play an important role in residential property assessment. Single-family and residential multi-family property assessments are sensitive to neighborhood boundaries. Neighborhoods are nearly always used in statistical regression models to produce initial assessed values, and comparable properties are nearly always selected from within neighborhoods for the purposes of appeal. See data notes for additional information.

This data contains every residential Property Index Number (PIN) and corresponding Assessed Values from significant stages in the assessment process.

This is the data set of residential sales used by the Cook County Assessor in their Computer Assisted Mass Appraisal system used to assess residential property values. This data set contains property information for every arm's-length residential sale in Cook County where class is within a specified list of classes. For disclaimers, see data set narrative at https://datacatalog.cookcountyil.gov/stories/s/p2kt-hk36