Distinguished Hospital Award Patient SafetyTM Methodology 2007 - 3
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b) Adjusted the expected (predicted) counts so that the total observed count was equal to the total
expected for each PSI, and for each year-CMI level combination. For example, if CMI level 1 had 2,000
predicted events and 1,800 observed for a given year and PSI, each of the hospitals in this group would
have its predicted value reduced by 10 percent. If the CMI level 6 had 3,000 predicted and 4,000
observed, those hospitals would have the predicted values increased by 33 percent.
3. HealthGrades statistically compared the observed rate to the expected rate to produce a z-score for
each PSI. To normalize the effect of the 13 indicators, these z-scores were rescaled to a mean of zero
and standard deviation of one. The average of the 13 resulting scores determined a hospital's ranking.
4. HealthGrades divided the hospitals into two peer groups: teaching and non-teaching. To identify the
teaching peer group, HealthGrades used data from the Medicare Cost Reports (Form CMS-2552-96). A
facility was considered a teaching hospital if they answered "yes" to the question: "Is this a teaching
hospital or affiliated with a teaching hospital?" Hospitals that received substantial Indirect Medical
Education payments in 2005 were also classified as teaching hospitals. Independent verification by
phone was used for hospitals answering "yes" with zero Indirect Medical Education payments.
5. To be considered for the Distinguished Hospital Award for Patient Safety
TM
, hospitals had to be rated in
at least 19 of 28 HealthGrades cohorts and have a current overall HealthGrades star rating of at least
2.5. The final data set included 752 teaching hospitals and 857 non-teaching hospitals.
6. From this final data set, HealthGrades identified both teaching and non-teaching hospitals in the top 15
percent as "best performing" and these hospitals are recognized as Distinguished Hospital Award for
Patient SafetyTM recipients. These 242 hospitals represent less than five percent of the total hospitals
evaluated.
Hospital Type
Number of Best
Performing Providers
Teaching Hospitals
113
Non-Teaching Hospitals
129
Limitations of the Data Models
It must be understood that while these models may be valuable in identifying hospitals that perform better
than others, one should not use this information alone to determine the quality of care provided at each
hospital. The models are limited by the following factors:
·
Cases may have been coded incorrectly or incompletely by the hospital.
·
The models can only account for risk factors that are coded into the billing data. Therefore, if a
particular risk factor was not coded into the billing data (such as a patient's socioeconomic status
and health behavior) then it was not accounted for with these models.
·
Although HealthGrades has taken steps to carefully compile these data, no techniques are
infallible; and therefore, some information may be missing, outdated or incorrect.
Please note that if more than one hospital reported to CMS under a single provider ID, HealthGrades
analyzed patient safety data for those hospitals as a single unit. Throughout this document, therefore,
"hospital" refers to one hospital or a group of hospitals reporting under a single provider ID.
