Our hospital bill is about to get a thorough examination. Acting on the suggestion of her top data crunchers at the department's Centers for Medicare and Medicaid Services (CMS), Health and Human Services Secretary Kathleen Sebelius released an enormous data file on May 8 that reveals the list—or "chargemaster"—prices of all hospitals across the country for the 100 most common inpatient treatment services in 2011. It then compares those prices with what Medicare actually paid hospitals for the same treatments—which was typically a fraction of the chargemaster prices.