One of the seminal achievements in the patient safety field, the Keystone ICU project accomplished impressive short-term and long-term reductions in health care–associated infections in Michigan ICUs by implementing checklists and improving safety culture. This follow-up study also demonstrates the cost-effectiveness of the program, as the money saved by preventing infections greatly outweighed the cost of the intervention itself. Substantiating the business case for quality in this fashion will further stimulate wide dissemination of proven safety interventions.