Hospital Quality Guide Methodology 2006 9
© Copyright 2006 Health Grades, Inc. All rights reserved.
May not be reprinted or reproduced without permission from Health Grades, Inc.
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
The AHRQ software uses advanced statistical algorithms that can predict the number of patient safety
incidences likely to occur at a hospital based on such factors as the mix of types of cases treated at that
hospital. This information is used to determine an overall patient safety rating for a hospital as well as an
individual rating for each patient safety indicator.
Overall Patient Safety Score
To be eligible for a patient safety overall score, a hospital must have had outcomes in 11 of the 13 patient
safety indicators. Hospitals with 10 or fewer patient safety ratings were not eligible to receive an overall
patient safety score, but may have individual patient safety indicator ratings.
To determine the overall patient safety score by hospital, HealthGrades performed the following steps.
HealthGrades statistically compares the actual rates of individual patient safety events to the predicted
rate to produce a score for each individual patient safety indicator that had a sufficient volume at a
The average of the resulting scores determines a hospital's ranking. Star ratings are then assigned as
Best (Top 10%)
As Expected (Middle 80%)
Poor (Bottom 10%)
Individual Patient Safety Indicator Rating
To determine a patient safety indicator score for each of the 13 PSIs for each hospital, HealthGrades
statistically compares the actual rate of individual patient safety event to the predicted rate. HealthGrades
Displays if the PSI was Best, As Expected, or Poor.
Shows how many patients were affected per 1,000 patient discharges.