The authors assessed the costs of hospital-acquired infections using rigorous econometric methods on publicly available data, controlling for the interdependency of length of stay and the incidence of hospital acquired infection, and estimated the cost shares of different payers. They developed a system of equations involving length of stay, incidence of infection, and the total hospital care cost to be estimated using simultaneous equations system. The main data came from the State of New Jersey UB 92 for 2004, complimented with data from the Annual Survey of Hospitals by the American Hospital Association and the Medicare Cost Report of 2004. The authors estimated that an incidence of hospital acquired infection increases the hospital care cost of a patient by $10,375 and it increases the length of stay by 3.30 days, and that a disproportionately higher portion of the cost is attributable to Medicare. They conclude that reliable cost estimates of hospital-acquired infections can be made using publicly available data. Their estimate shows a much larger aggregate cost of $16.6 billion as opposed to $5 billion reported by the Centers for Disease Control and Prevention but much less than $29 billion as reported elsewhere in the literature.