CalHospitalCompare.org

About the Ratings

The 216 hospitals rated on this site account for 78% of hospital admissions in California and the conditions and procedures rated (heart attack, heart failure, heart bypass surgery, pneumonia, and maternity) are the five most common reasons for being admitted to a hospital. In addition, there are measures applicable to all surgical patients or all medical patients (patients admitted to the hospital for an illness that is not treated with surgery). Other conditions and measures will be included in future updates to this site.

Hospitals on this site are rated on quality and timeliness of care for several conditions, as well as patient experience with overall, medical, surgical, and maternity care, and adherence to recommended patient safety practices.

With the exception of some patient safety measures, hospitals are rated on a five point scale, based on their performance:

• Superior - Hospital performed well above average compared to other hospitals on this measure.
• Above average - Hospital performed better than average compared to other hospitals on this measure.
• Average - Hospital performed within the average range compared to other hospitals on this measure.
• Below average - Hospital performed worse than average compared to other hospitals on this measure.
• Poor - Hospital performed well below average compared to other hospitals on this measure

How the Ratings Are Assigned

Hospital performance is evaluated compared to benchmarks of high, middle, and low performance. The benchmarks used were specific to each condition, but as a general rule, the top 10% of national performance on a measure was used as the high benchmark, and the national average on a measure was used as the middle benchmark. Performance 10% below the national average was used as the low benchmark.

Because CHART hospitals are releasing patient experience survey data and some patient safety measures before the rest of the nation, these hospitals can only be compared to each other, using their average performance, as well as top and bottom 10% performance levels, as the three benchmarks.

Applying a Margin of Error to Data

Choosing benchmarks is only the first step in assigning a rating. This is because it would be misleading only to compare a hospital's performance rate to the benchmarks, especially if that hospital has only treated a few patients with a specific condition or procedure. For example, a hospital that does only one heart surgery will have a death rate of either 0% (if the patient lives) or 100% (if the patient dies). Based on the outcome for one patient, it is difficult to determine how the hospital would perform for many surgeries.

Because it may not be possible to determine if the performance on a procedure or treatment has been measured accurately, the ratings on this site use a "margin of error," just as many news polls do. For hospitals that have only a few patients with a particular condition, the margin for error in the measurement of their performance in that condition is broad, while for hospitals with hundreds of patients the margin for error is narrower. (For this reason, for any single measure on this site, two hospitals with the same rating may have very different percentages shown.)

In rating the hospitals, the margin for error is taken into account by calculating an estimated range of hospital performance for each condition, with the range wider for hospitals with fewer patients and narrower for hospitals with many patients. The data for the specific condition are then checked to determine whether this range includes any of the performance benchmarks (low, middle, or high, where higher means better performance) and a performance score of superior, above average, average, below average, or poor is assigned.

The five scores were assigned using the low end (L) of the range of each hospital's estimated performance and the high end (H) of the range and comparing them to the low, middle and high benchmarks.

Below the Low Benchmark	Between the Low and Middle Benchmarks	Between Middle and High Benchmarks	Above High Benchmark	Ratings
			L & H	Superior
		L	H	Superior
		L & H		Above Average
	L		H	Above Average
	L	H		Average
	L & H			Average
L			H	Too Few Cases to Rate (Range too Wide)
L		H		Below Average
L	H			Below Average
L & H				Poor

Time Periods for Data Collection

In all cases, we use the most recent data available. However, the time periods vary for different conditions. The time periods are:

• Heart Attack, Heart Failure, and Pneumonia Care (except mortality rate for pneumonia): July 2006 through June 2007.
• Coronary Artery Bypass: Calendar year 2005.
• Maternity Care: Calendar year 2006 (except Patient Experience Surveys).
• Pneumonia Mortality Rate: Calendar years 2002 through 2004.
• Critical Care: January through September 2007.
• Patient Safety: Surgical Infection Prevention, July 2006 through June 2007; Hospital-Acquired Pressure Ulcers, January through September 2007.
• Patient Experience Surveys: July 2006 through June 2007.

Adjustments for Variations in Patient Mix

There are many factors that have an impact on how well a patient with a given condition or procedure will do, and these factors have an effect on how the performance ratings for those conditions are calculated as well. For instance, having diabetes can reduce your chances of surviving heart surgery, so a hospital with more diabetic patients than average should have its death rate adjusted. However, having diabetes does not prevent the nurse from checking your wristband before giving a medication, so there should be no adjustment for diabetes in that measure. Similarly, maternity patients nationwide report much better experiences with care (because they have plenty of time to identify a preferred hospital and they get to take home a baby) than routine medical or surgical patients, so a hospital that does not do any maternity care should have its overall rating adjusted up to allow comparisons of overall patient experience to hospitals that do have maternity care.

Therefore, for each condition, the most modern, state-of-the-art adjustment procedures available were used to account for variations in patient mix. The following organizations provided the rules for collecting the data and adjusting for patient differences when necessary:

• Heart Attack, Heart Failure, and Pneumonia Care (except Mortality Rate for Pneumonia): The Joint Commission and the federal Medicare program.
• Pneumonia and Coronary Artery Bypass Mortality Rates: the California Office of Statewide Health Planning and Development.
• Maternity Care (except Patient Experience Surveys): the California Office of Statewide Health Planning and Development.
• Critical Care: The California hospitals in the CHART project.
• Patient Safety: Surgical Infection Prevention measures, the Joint Commission and the federal Medicare program; and Hospital-Acquired Pressure Ulcer (HAPU) rates, the California Nursing Outcomes Coalition.
• Patient Experience Surveys: the National CAHPS Benchmarking Database (the national center for collecting patient surveys).

To reduce the impact of the different patient characteristics among the different hospitals, and thus to help assure the accuracy of the performance reports, each hospital's scores were adjusted to reflect the scores the hospital would have received had its patient response sample included an average mix of patient characteristics. In general, however, the effect of the adjustment process on participating hospitals' scores was small.

Maternity Data

For several elements in the maternity data—C-section rates, rate of vaginal births in mothers who have had a C-section previously (vaginal birth after Cesarean, or VBAC)—there is no generally agreed upon approach to rating this data; therefore, no performance measures are assigned.

However, the data can be useful, especially for an expecting mother or couple. The C-section rate, for instance, can help you know the hospital's general tendency to switch from trying to deliver vaginally to doing a C-section. If you want to do everything possible to have a typical vaginal delivery, you may prefer to use a hospital with a low C-section rate.

The issue with VBACs is similar, except that there are some hospitals that have decided they do not want routinely to allow women to attempt a vaginal birth if they have had a prior C-section. Again, this is a matter of preference rather than quality or safety of care, but if you have had a C-section and really want to try to have a vaginal birth, you need to choose a hospital at which this is permitted.