New Jersey physician Dr. Jeffrey Brenner used data analysis to tackle one of the U.S.’s biggest problems: rising health-care costs. Using a database of 600,000 hospital visits, he built a map linking claims to patient’s addresses. He found that just 1% of patients were responsible for 30% of hospital bills. Driven by that information, he founded the Camden Coalition of Healthcare Providers, which dispatches caseworkers to make home visits to the patients with the most problems. The aim is to help patients stay on their medications and out of the emergency room.