Health Grades Hospital Quality Guide Methodology 20072008 (Page 7)

Hospital Quality Guide Methodology 2007 - 2008 7

May not be reprinted or reproduced without permission from Health Grades, Inc.

To help consumers evaluate and compare hospital performance, HealthGrades analyzes patient data for
virtually every hospital in the country to determine patient safety outcomes.
HealthGrades uses Medicare inpatient data from the MedPAR database (purchased from the Centers for
Medicare and Medicaid Services; 2003 through 2005 data) and Patient Safety Indicator software (QI
Windows Software, Version 3.0a) from the Agency for Healthcare Research and Quality (AHRQ) to analyze
the following 13 patient safety indicators (PSI):

Prevention of death in procedures where mortality is usually very low

Lack of pressure sores or bed sores acquired in the hospital

Ability to diagnose and treat in time

Absence of foreign body left in during procedure

Avoidance of collapsed lung due to a procedure or surgery in or around the chest

Lack of infections acquired at the hospital

Absence of hip fracture after surgery

Avoidance of excessive bruising or bleeding as a consequence of a procedure or surgery

Adequate organ function and electrolyte and fluid imbalance after surgery

Avoidance of respiratory failure following surgery

Lack of deep blood clots in the lungs or legs after surgery

Avoidance of severe infection following surgery

Lack of surgical wound site breakdown

For most indicators, the AHRQ software uses advanced statistical algorithms that can predict the number of
patient safety incidences likely to occur at a hospital based on the mix of types of cases treated at that
hospital. For those indicators without predicted results from the AHRQ software, predicted results were
generated by grouping the populations according to risk, and assigning average group values to patients in
each group. This information is used, in part, to determine a HealthGrades overall patient safety rating for
a hospital as well as an individual rating for each patient safety indicator.

Individual Patient Safety Indicator Rating

To determine a patient safety indicator score for each of the 13 PSIs, HealthGrades statistically compares
the actual rate of individual patient safety events to the predicted rate.
HealthGrades then displays if the PSI was Best, As Expected, or Poor.

Best Fewer patients were affected than expected.

As Expected About the same number of patients were affected as expected.

Poor More patients were affected than expected.

When a hospital is not rated, it means the hospital had too few cases to be eligible to receive a
patient safety rating.

Health Grades - Hospital Quality Guide Methodology 20072008 (Page 7)