The goal is lofty: improve and expand health care for millions of Texans. But with billions of dollars at stake and the new project under way before the rules are even written, decisions made over the next few months are causing anxiety in many Harris County hospitals. The new rules—part of a complicated, first-of-its-kind project approved by the federal government—will determine who gets paid for providing charity care, and how much. Hospitals that historically received the most government reimbursement for charity care are not guaranteed to prosper under the new rules.