Tracking the Cook County Jail and Community Corrections Population

The Pretrial Fairness Act (PFA), which went into effect in Illinois on September 18, 2023, abolishes cash bail and imposes strict new limits on the use of pretrial jail detention for people accused of crimes. As part of our evaluation of the PFA, we’re collecting jail population data from counties across Illinois. We developed a data tool that tracks the daily Cook County Jail and Community Corrections population. Data is scraped from the CCDOC Population Data Jail Population Data report daily. We’ve built two visualizations to track this data over time.

View This Data As a Table

To view and download this data as an interactive table, click here

How We Collect This Data

We use a technique common amongst data journalists called git scraping. This allows us a lightweight way to run the ETL needed to parse and store daily pdfs into a clean .csv. The github repo is public and can be found here.

Data begins at 01-01-2018 and is updated daily with a day lag – the pdf scraped is the pdf uploaded on the day prior from the script execution. Data collected between 2018-2020 is taken from a prior Loyola Center for Criminal Justice Project and was collected by hand. We imputed the few jail records where the Cook County Jail failed to add a pdf report for that day. Data from 2021-present is populated through a backfill of the pdf scraper that triggers daily. Both files were combined to create the data/cook-jail-data.csv file that updates daily.

This research is supported by Award No. 15PNIJ-21-GG-02807-RESS awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice. The opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect those of the Department of Justice.