Measuring Quality

Quality data come in many forms. Information can be pulled from clinical records, billing information or administrative codes that are used to classify diagnoses and conditions. The data is run through complex math models to try and make it meaningful.

Because quality data are pulled from multiple sources, documentation plays a crucial role in measurement. When treating a patient, a practitioner needs to accurately and consistently report the specific diagnosis and document the treatment that the patient receives. If the practitioner makes an error in the documentation process, it can have a negative effect on the hospital's rating—even if the patient's clinical outcome is optimal. Stanford Health Care has implemented a state-of-the-art electronic documentation system and trained our health care practitioners to ensure that documentation is accurate and specific. Accurate documentation helps to limit reporting errors, so our clinical and administrative staff can better identify true clinical improvement opportunities.

Factors that affect quality

The number of patients a hospital treats for a condition or procedure and the severity of a patient's illness when they check into a hospital are two factors that can affect a hospital's quality rating. Some evidence suggests that the quality of care for patients with certain conditions or procedures is related to the number of patients treated at that hospital for those conditions or procedures, especially if the procedure is risky or extremely difficult.

The severity of a patient's illness is also a key factor in measuring the quality of care at a hospital. A standard measure to compare patients' severity of illness between hospitals is called the Case Mix Index (CMI). Hospitals with a high CMI treat a greater number of severely ill patients, which impacts overall clinical outcomes.  

Stanford Health Care has one of the highest CMIs in the country because we specialize in caring for complex diseases and conditions. Despite our high CMI, we maintain very positive outcomes, even when compared to hospitals that treat patients with illnesses that are less severe. 


Some information you may find helpful, and other information may be confusing. The most important things you can do are request quality data and ask questions.

  • Is there quality data available for the hospital where my procedure will take place?
  • Do you recommend the hospital for my procedure or condition?
  • Is the hospital accredited by the Joint Commission?
  • How many patients has the hospital treated for my condition or procedure?
  • How does this hospital compare to others for my condition or procedure?
  • What have other patients experienced at this hospital?
  • Will care at this hospital be covered by my insurance?