The Pulitzer Board announced Monday that ProPublica Illinois and The Chicago Tribune were finalists for the 2018 Pulitzer Prize for Local Reporting for their “The Tax Divide” investigation into Cook County, Illinois’ unfair property tax assessment system. The series is the first Pulitzer Prize finalist for ProPublica Illinois, a nonprofit newsroom that launched just six months ago as ProPublica’s first regional, state-based unit. ProPublica’s partnership with NPR was also a Pulitzer finalist for Explanatory Reporting for the “Lost Mothers” series. It was ProPublica’s eighth and ninth Pulitzer finalists in 10 years of publishing.  

For decades, controversy had swirled around the assessment system in Cook County. Residents and business owners suspected their property taxes were based on inaccurate assessments, overvaluing many low-priced properties while undervaluing many higher priced ones. But the process was so opaque and convoluted that few people understood it, and most reporters lacked the technical and analytical skills to challenge it.  

Lead reporter Jason Grotto — who started the project as a Chicago Tribune staff writer and continued his investigation after joining ProPublica Illinois — set out to prove statistically that the assessment system was deeply flawed in ways that created groups of winners and losers. He studied the arcane system for two years, reading thousands of documents, analyzing more than 100 million electronic records, and interviewing dozens of experts, attorneys and property owners affected by the unfounded assessments. The resulting four-part series exposed a system  that punished small businesses and poor homeowners, gave the wealthy undeserved tax breaks and lined the pockets of politically connected tax attorneys.

Grotto began his reporting with a focus on residential assessments. He gathered data on single-family homes and apartment buildings to understand how average homeowners were affected. Assessment officials released the information he requested, never thinking that a journalist could process the reams of data or understand the complex regression models used to value residential property. But with the help of his sources, Grotto decoded the models and showed how the system treated poorer homeowners unfairly. The assessment system, it turned out,  reflects the racial and socioeconomic divisions that have long made Chicago one of the most segregated cities in America. Through neighborhood anecdotes, the series showed how the assessment system awards breaks to the already-privileged residents of wealthy and mostly white parts of the county, while laying new burdens on working class areas where most residents are black or Latino.

Grotto and his colleagues, which included ProPublica Illinois data reporter Sandhya Kambhampati and Chicago Tribune reporter Ray Long, also documented problems with commercial and industrial valuations, showing how insiders benefit from faulty assessments. The story gave voice to frustrated business owners who feel trapped by a system that forced them to pay for appeals, and it showed how the intricate ecosystem of politicians, attorneys and appraisers feeds off Cook County’s flawed assessments.

Reaction to the series was swift. The inspector general for Cook County launched an investigation almost immediately, and the county board president ordered a study of residential assessments by an outside consulting firm. The county board also required Assessor Joseph Berrios to testify at a public hearing about his methods — a remarkable move because Berrios is one of the most powerful politicians in Illinois and head of the Cook County Democrats. State and local lawmakers, concerned that the property tax system favored those who supported Berrios politically, introduced legislation to limit campaign contributions to the assessor.

Additionally, three prominent public interest law offices sued Berrios and the county, alleging violations of state and federal civil rights and housing laws. The suit draws heavily on “The Tax Divide” in alleging that the county’s assessment system under Berrios is “perpetuating institutional racism.” And in the Illinois primary election last month, a more informed electorate voted Berrios out of office.

“‘The Tax Divide’ gets right to the heart of ProPublica Illinois’  journalism: shining a light on abuses of power and betrayals of public trust, and holding that power to account,’ said ProPublica Illinois editor-in-chief Louise Kiernan. “Cook County residents not only learned that their property assessment system wasn’t fair — they also made their voices heard at the voting booth. Thanks to the project’s rigorous and undeniable analysis, policymakers are also making positive changes toward fixing the region’s broken assessment system.”