Chicago health officials had a serious problem. The city had long been trying to attack breast cancer among minorities with a program offering uninsured women free mammograms at Roseland Hospital in the predominantly black South Side. But black women – who are far more likely than white women to die of breast cancer – weren't getting screened. Because traditional public health outreach didn't seem to be working, the city's Department of Public Health decided to do something new: It turned to a Chicago-based data mining company, Civis Analytics, for help. Data mining, often employed by political teams and mass marketers, uses statistical analysis to find patterns within large data sets to project trends about individual behavior and demographics.