This project is the result of a collaboration between the Daily Herald and the Local Reporting Network of ProPublica, a nonprofit investigative outlet.

To report this story, the Daily Herald and ProPublica reviewed thousands of pages of state and local records obtained under Illinois’ Freedom of Information Act, lawsuit and bankruptcy court filings, and internal Sears documents. We also interviewed state and local officials, economic development experts and people with knowledge of the Sears deal.

To examine the long-term effect of the tax deals, ProPublica and the Daily Herald also commissioned a study by Illinois’ Center for Tax and Budget Accountability, or CTBA, a bipartisan, nonprofit research organization that also lobbies for fiscally responsible state government policies.

CTBA used a statistical method known as a “difference-in-differences,” which measured the economic impact of the Sears deal by comparing before-and-after economic trends in Hoffman Estates to similar, nearby communities over the same time period between 1980 to 2017.

M. Marit Rehavi, a member of ProPublica’s data science advisory board and an associate professor of economics at the Vancouver School of Economics, University of British Columbia, consulted on the analysis.

To read CTBA’s full study and for more information about the center’s data and methodology, please visit here.