Healthgrades, a for-profit provider of information of hospitals and doctors, is out with a new review of 4,500 hospitals in the United States.
The report says there is a big difference in patient care and risk of dying for some of the more common medical conditions and procedures.
It focuses on four key areas: coronary artery bypass grafts, hear attack , pneumonia and sepsis.
The rankings are based on analysis of data from the Centers of Medicare and Medicaid Services.
Hospitals with a five-star ranking had a 75 percent lower risk of dying and a 60 percent lower risk of complications, compared to those with a one-star ranking.
For example, here's how some area hospitals ranked: Northwestern had seven total five-star ratings; St. Joseph had six; Mercy had five; and Rush had three.
Critics say, like other national rankings, these reports do not account for all factors that can affect hospital outcomes.