U.S. News & World Report Best Hospitals List Shifts Methodology

Another change this year is a shift in a statistical approach called "factor analysis," in which the hospital received a scoring advantage if certain scores, for example, for patient volume, nurse staffing ratios, advanced technologies correlated with each other.

The magazine now considers the weight of each measure by itself in relation to medical outcomes. "Adding more nurses, for example, leads to improved care, no matter what relationship the nurse staffing measure does or does not have with any of the other measures."

The new Best Hospitals list includes statewide rankings of hospitals, an expansion of last year's subdivision, which looked at hospital rankings within certain metropolitan areas.

Other ingredients that make up these rankings include patient survival, infection rates, patient safety measures, nurse-to-patient ratios and responses from medical specialists to opinion surveys.