When a car rolls off an assembly line, the automaker knows exactly what parts, labor and facilities cost. Not so in health care, and now some health executives are trying to change that. Although U.S. hospitals account for the single largest chunk of the nation's $2.7 trillion in health spending, few of them can say how much it actually costs them to care for every patient they admit. Today, the Utah health system is one of a handful in the nation with a data system that can track cost and quality of care for every one of its 26,000 patients. Those data are shared with doctors and nurses for further input about ways to streamline cost and improve care.