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@ccao-data

Cook County Assessor's Office

The CCAO's Data Department creates models, tools, and analyses to improve Cook County's property tax system

🎉 We're hiring! 🎉

The Data Team is seeking a Director of Data Science in a role that unites data science best practices, innovation, and public service. Read more and apply by September 11.

Hi there! 👋

We're the Cook County Assessor's Data Department. We make predictive models to help determine the assessed value of every residential and condominium property in Cook County. We also make tools and reports to make the Cook County property system more transparent, predictable, and fair.

Our work

Our tiny team has done some big work since 2018. Here are some of the things we're most proud of:

Get involved

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  1. model-res-avm model-res-avm Public

    Automated valuation model for all class 200 residential properties in Cook County (except vacant land and condos)

    R 45 11

  2. data-architecture data-architecture Public

    Codebase for CCAO data infrastructure construction and management

    R 6 4

  3. model-condo-avm model-condo-avm Public

    Automated valuation model for all class 299 and 399 residential condominiums in Cook County

    R 11 4

  4. ptaxsim ptaxsim Public

    R package for estimating Cook County property tax bills

    R 17 4

  5. model-sales-val model-sales-val Public

    Heuristics for detecting outlier and non-arms-length sales

    Python 2 1

  6. wiki wiki Public

    Handbook, how-tos, and other documentation

    HTML 5 1

Repositories

Showing 10 of 28 repositories
  • model-sales-val Public

    Heuristics for detecting outlier and non-arms-length sales

    ccao-data/model-sales-val’s past year of commit activity
    Python 2 MIT 1 19 4 Updated Sep 11, 2025
  • pinval Public

    Prototype PIN VALuation report

    ccao-data/pinval’s past year of commit activity
    R 0 0 13 2 Updated Sep 11, 2025
  • data-architecture Public

    Codebase for CCAO data infrastructure construction and management

    ccao-data/data-architecture’s past year of commit activity
    R 6 4 75 6 Updated Sep 11, 2025
  • assesspy Public

    Python package for measuring assessment performance

    ccao-data/assesspy’s past year of commit activity
    Python 2 AGPL-3.0 0 1 1 Updated Sep 10, 2025
  • model-res-avm Public

    Automated valuation model for all class 200 residential properties in Cook County (except vacant land and condos)

    ccao-data/model-res-avm’s past year of commit activity
    R 45 AGPL-3.0 11 27 4 Updated Sep 10, 2025
  • extract-permits Public

    Script and workflow for permit data extraction

    ccao-data/extract-permits’s past year of commit activity
    Python 0 0 4 1 Updated Sep 10, 2025
  • .github Public

    Source for org-level README

    ccao-data/.github’s past year of commit activity
    0 0 0 0 Updated Sep 10, 2025
  • assessr Public

    R package for measuring assessment performance

    ccao-data/assessr’s past year of commit activity
    R 7 AGPL-3.0 2 1 2 Updated Sep 4, 2025
  • wiki Public

    Handbook, how-tos, and other documentation

    ccao-data/wiki’s past year of commit activity
    HTML 5 1 12 0 Updated Sep 3, 2025
  • ccao Public

    R package of functions and datasets used throughout the CCAO assessment pipeline

    ccao-data/ccao’s past year of commit activity
    R 1 AGPL-3.0 1 4 0 Updated Jun 26, 2025