In-person and Online: Generating 1.9 Million Static Web Pages to Explore How the Cook County Assessor’s Statistical Model Valued Your Home #656

The Data Science team at the Cook County Assessor’s Office (CCAO) is responsible for estimating the values of over a million homes in Cook County using public sales data. They value those homes using a gradient boosted decision tree model. Although the model’s source code may be open for the public to read, it can be difficult to explain how it works in a clear, accessible way. Statisticians can speak the language of tree depth, SHAP values, and vertical equity measures, but what most people want to know is: “What sales and characteristics did the model use to value my home?”

Enter the CCAO’s Home Value Report (HomeVal): A web app that uses an experimental algorithm to show the top five sales that were most significant for the model’s estimation of your home’s value, alongside roughly 100 characteristics that the model used to compare your home to recent sales – characteristics like square footage, age, school district, and distance to transit.

In this talk, the CCAO Data team will explain how and why they built HomeVal. They’ll dive into the nitty-gritty details of how they designed and implemented the app — from developing an AI explainability algorithm, to scaling that algorithm across every home in the County using high-performance Python code, to generating 1.9 million static HTML pages in roughly one hour using Hugo and GitHub Actions.

This event will be in person, but you can also tune in via livestream. Doors open at 6pm. The livestream and announcements will start around 6:30pm CDT.

In-person: i.c.stars, 750 N Orleans, Suite 500 (5th floor), Chicago IL.

For more information on our in-person events, please see our COVID Policy.

RSVP In-person attendees should RSVP beforehand. As occupancy limits permit, walk-ins will be allowed to enter.

There will be food! We will be serving Costa Rican empanadas, chicken casado and rice from Irazu!