An unprecedented analysis by the Chicago Tribune reveals that for years, the Cook County property tax system created an unequal burden on residents, handing huge financial breaks to homeowners who are well-off while punishing those who have the least, particularly people living in minority communities.

The problem lies with the fundamentally flawed way the county assessor’s office values property. The valuations, a crucial factor when it comes to calculating property tax bills, should be fair, transparent and stand up to scrutiny. But in Cook County, Assessor Joseph Berrios has resisted reforms and ignored industry standards while his office churned out inaccurate values.